>>48979061I haven't gotten a shadow hundo, that's why you don't see any.
I have 2 shadow Metagross and 2 shadow Dragonites at level 40. They're the only ones I've gotten that have been over 90% when caught, but that wouldn't have been 100% when purified, so I've kept them.
I wouldn't power up anything below 91% for any purpose, but I refuse to power up anything below 100% past level 40. If a Pokémon becomes 100% when purified, I always purify, unless I already have all of it's evolutionary stages as 100 IVs.
100% IVs > Anything else. I collect them, I don't care about performance.