Hey so since i farm act2 a lot i found out this trick, after you defeat Belial there is a 4-5 sec gap where you can put your MF gear on, and it counts! I belive it works on Diablo too but im not that far. Until now i was switching at 200k hp and i was getting 1 shotted. Enjoy! I got 4 rares with 280%MF (My pet is full MF gear too)