Although scaling may well induce nausea, the issue with current VT implementations is the effective tunnel vision meaning that hat switch view swapping is virtually (pun intended) a required function to remain competitive in terms of air combat. I notice that the default FOV for the Rift version of AH is 90 which I think is a bit low. I would have thought somewhere from 100 to 120 would be about right in terms of accounting for peripheral vision.
I had not thought of using Rift and Trackir concurrently, will have to do some research. Moving home at moment so no time to fly but hoping I will get on next week some time, if the internet connection at the new house works, gonna try it tomorrow.