My ECZ-G valve seats/bosses need to be cut for beehive valve springs. The spring OD is 1.25/ID is 0.845. The viton seals are 11/32 x 0.500 with an OD of 0.546. 

What size valve seat cutter should be used? 

I think I'm making this more complicated than it has to be for my target level of performance for a street engine.