Question My 3dof motion simulator

Hi buddy. Good to hear that you got your rig moving with simtools but not so good about the heave not working. I did think that your lever arms were going to be to long but you made such a nice job of them i didn't want to mention it unless you had problems. I would suggest that you made some new ones for testing with holes drilled all the way along them as close together as you can get (10mm is ideal) so you can adjust the centre to centre point. I would start with a 50mm ctc to start with to get the rig moving as you want it to then increase the lever length by 10mm increments testing after each adjustment. Once you have found the sweet spot then you can make nice levers to replace the test ones.
For your rig i wouldn't be using pitch and roll as these are used to simulate the car angles and not the g forces that the driver feels. I would be using surge, sway and heave instead.
As for the motion compensation i cant help as i dont use VR. I have a 3 screen setup and an lcd dashboard and button box instead. I have tried VR but made me feel quite ill so didnt take it any further. I do know that one of the top sim builders on this site in my opinion @SeatTime has removed his sim from one of the best diy 6 dof platforms that i have ever seen and chosen to go the g system route instead. You would have to ask him why but id suggest it was due to motion cueing and how fast the rig responds. His 6 dof was a thing of beauty built completely from carbon fibre (actuators and frame). He must of spent 100's of dollars and weeks of time to build and develop it.
Could you post some pictures of the SMC3 settings that you are using and maybe a video of your rig in action. We may spot something you are over looking or maybe throw you some pointers on how to improve things. It would be good to see it working buddy.