MrC -
Do you want wood screws or cap screws that can be used with a blind nut? The actual size is, I believe, an English #3 for the .049. A #3x48 socket head cap screw should work OK. Head diameter is .161" . Another option would be either the #2 or #3 socket head servo mounting screws - some have a washer head, but it could be easily ground down to fit nicely.
andrew
Sources:
socket head cap screws:
www.mcmaster.com
servo screws: Microfasteners; RTLFasteners; Fastener-Express