Model Train #00-90 screws with non-slotted heads?

My model trains use #00-90 machine screws to hold on the couplers. The vendors supply slotted heads, which can be really difficult to use. I've searched several of the major web screw suppliers, and even McMaster-Carr, my favorite go-to only has them in slotted. I know this size is used in a lot of computer equipment, so I'm sure someone makes them in phillips at least, if not other heads.

Where can I get #00-90 machine screws with phillips or torx drive? What is the go-to place to get all the super-tiny machine screws in today's gadgets?

I realize it's not the usual iFixIt fodder, but help me repair my trains!