No guessing involved.
The 38mm should work fine but since I am going for least amount of boost to start where most people are going for max the 38mm can not bleed enough off.
As Dave said I could take the 38mm apart, pull out the spring, ad manually hold it open and still make 8 lbs of boost at 4,000 rpms ! :o Talk about spooling quickly.
Looks like the 46mm will go on Monday if everyones schedules line up.