StewMac carries neck attachment ferrules to use in place of a plate on a countoured heel. You may be able to find them somewhere else too - just thought it was a great idea so that the screw head can be recessed and not bite your hand.

BTW there's nothing magic about stainless steel screws - Home Depot has screws absolutely identical to "pickguard mounting screws" that cost much more. Just make sure you measure at least THREE times in this case 'coz going thru the fingerboard would not be cool.

Chip