1.To the chap who suggested using a V2/ 300mm combo. I've tried it. Bought a V1/ FT-1 but really, it's nowhere near as good as you might expect. Plus, it wont even recognise the 50-500 OS. 'Been there, tried it, failed it, fu**it', as we used to say in the Army.
2.Frame rate. The OM-2 could move 5.5 fps with a motor drive and wet film. That was plenty. You might want more, but who really NEEDS more?