So, I'm getting ready to start a new game, and am planning to include college feeders (and maybe a small int'l HS feeder). (Actually, the game crashed last night after I had set up my feeder, losing 1 hour of typing in college names

but I digress)
When the time comes to delete the oversupply of 5 star MR, how do I go about doing that? Do folks do it when the draft pool is announced, or is there something that should be done before (i.e. deleting them while still in college)?
And how many deletions are we talking about? How many 5 star MR should be left for a normal 30-32 team draft?
Thanks for any advice.