Im with Tom and others here - using a hopper to try and limit your ROF is ridiculous (not directed at you dan just the idea in general)
you will need a virtue board or such like to do it electronically - i know the masters is a bit slack but theres no way that using the hopper would be legal - I've seem someone advise people to use this method on other threads here and its fundamentally wrong .
BTW your also limiting yourself here if your hopper doesnt feed at 15bps reliably which a lot off eggys wont