Question 6DOF RC servo accurate move ?

Hi all,
I don't really know how to make myself clear so I hope the question will be understandable.
As you can see from this picture below, I built a 6DOF platform with RC servo that i am currentely using with simtools to get acquainted with the software.

Y is my surge axis, while X is the sway one. servos 1 2 and 3 are located to the right, when 4 5 and 6 are to the left.
I have started playing with simtools and the axis assignement settings, and franckly speaking, it is working pretty well so far, and I manage to make the platform move "almost" the way I want.
"Almost" is an important word as it the reason for my question here.
Now, I have studied a bit the moves of a 6DOF stewart platform and the math behind it are quick complex (Well, it depends for who ). If I understand correctely the way Simtools, it "only" gives a linear input to the actuar, based on the data received (pitch, roll, etc..) and the axis assignement. And it is a symetrical function.
This works very well for some axis, but it is not ideal for all of them. Again, not sure I am being clear here but I 'll try to explain myself.
Let's take the simplest DOF of all: Heave. All actuactors should move in the ssame direction, with the same amount of travel. Easy to setup with SImtools.
ANother simple one, Yaw, the actuators should work in a reserve way by pairs. In my case, 1 and 6 are reversed, 2 and 3, then 4 and 5. Again simple to setup with simtools.
A little bit more interresting, Roll. I see a lot of configuration where it is configured this way: 1 and 2 are set equally. 5 and 6 are reversed compared to 1 and 2. 3 and 4 are not even used. Doing so, this gives something close to a roll, but it is actually not "exactely" a pure roll. Indeed, a much better Roll is set as such:
Axis 1 = 3/4 *X, Axis 2 = X, axis 3 = 1/4 * X, Axis 4 = 1/4 * X (Reversed), Axis 5 = X (Reversed), Axis 6 = 3/4 *X (Reversed). With X being anyvalue depends on the travel switch if any.
In this configuration, the Roll looks much much like a "pure" Roll only, and not a combination of roll and yaw, and who knows what, as it is with initial settings. Does that make sense so far ?
Well, but this is still working very well with Simtools since this mouvement is symetrical. (Y symetry axis)
Same goes for the Pitch move, and even though it is not fully symetrical, it wotks pretty well with simtools settings.
Now, in my opinion, real problem comes with Surge and Sway, where there is no clear definition of the amount of travel to be done by the actuator to perform a "pure" Surge or sway.
I used this video below (and it's associated Excel file) to understand better the motions of sway and surge and set simtools correctely.

The problem with sway and surge, is that each servo has a completely different travel length whether it is surge positive or negative, and same for sway positive or negative.
Se settings the axis for one specific side (say positive surge) works well for the surge direction, but is way of with negative surge. This is clearly what I could experience with my 6OF motion platform.
This, IMO, is due to the fact that settings sith simtools are linear AND Symetrical, and we cannot add more complexe mathematical calculation.

All what was written above are pure assumption and I might be completely wrong. So please don't hesitate to show me the way, and maybe there is simply something I am missed with Simtools.

Cheers guys.

you would have to write a plugin to do the math for you. simtools is setup for plugins but as @noorbeast stated there isn't currently a plugin that deals with this issue. Although I haven't tried it with my 6 dof some use "ian's BFF software". I just tune to the feel personally. I dont use yaw and roll as they do not work properly for my 6dof. IMHO the rest is doable with tuning.

EDIT: what you see when watching a sim move is vastly different from how it feels. sometimes the right feel looks completely wrong from outside of the rig.

@noorbeast @bruce stephen
Thanks both for your answer, I am glad that you understand my point
Ok I get the idea that there is no advanced mathematical function for 6DOF with simtools (Yet) and I fully agree that Simtools gives pretty good results already without this feature.
As per the tuning side, I have no doubt the feelings on a full size p^latform helps a lot doing the proper setup. But as mine is simply a scale model so far, I can only rely on the moves made by it and compare it to reality. I have no problem with Heave, Yaw and Roll moves that are true to reality. Pitch is not perfect but really acceptable. Only sway and surge are not behaving in a symetrical way, which is not very good in my opinion. I'll try to play with the settings, even filters to see if I can improve this behaviour. I might also want to ask other member's settings to compare and find the best alternative, eventhough this is pretty much hardware dependent.
As per "Ian's BFF software", I'll have a look at it out of curiosity.

Oh, I thought it was somewhere in the comments. I might be wrong here, but I have the EXcel file which is for sure the one use in this video. Not sure where I got it from then.
ANoway, I can share it but of course, I don't want to take the credit for that as it is clearly not mine. The owner of this file seems to be the one who made the video, 1982DannyW.
I used this file to understand the moves of a 6DOF motion platform, it is pretty interresting if you go through the maths behind it (again the file is very helpfull for that). It can even be customized to match the exact dimension of a rig.
If such a feature could be included in Simtools, that would be amazing.
Here is file enclosed. You will have to replace the .txt by .xlsm as I couldn't upload a file with this extension. If it doesn't work, just let me know and I'll share it in a different way.

EDIT: I just realised the name of the owner of the Excel file is Danny Waters. Hope he is fine with me sharing his file.

@yobuddy
Any news regarding the discussion we had in this thread, any chance we can see an option for 6DOF accurate move in Simtools or it is simply not in the pipes ?
Thanks mate in advance.

Hi FoxONE42, I would like to build a similar platform as you did using mini RC servo, could you give some info about the code you used I think with arduino and possibly the simtools settings to move it. I looked around for this info but I couldn't find anything specific. In the meantime, I have printed the platform for the servo that should arrive in these days ....

Thanks, could you tell me what are the letters that identify the axis in simtools as well
'R' 'L' 'F' 'B' and....

Thanks you are always very kind