90% of the really critical training for existing pilots will be on the systems. It'll be mostly classroom and a bit of SIM work. The need for flying training for guys that have already got combat experience flying SU-27's is likely minimal. Chances are these Ukrainian pilots have more real combat and tactical experience than any of our people have.
How hard can it be to take someone from being combat ready flying an SU-27 to being combat ready flying an Tornado, or much better, a Typhoon?