As someone else mentioned, I would just keep doing Tyranitar and Machamp raids till they rotate and try to get higher and higher IVs and better moves first...If it's 100% or 97%, then that's probably good enough to use a TM...My guess is raid bosses will eventually rotate maybe every 2-4 weeks.
I should have done that with my Machamps thinking about it more...but the ones I powered up were 95% and 91%...
Another 2 were already level 29 and level 25 (so saved dust)...