use regular 10-32 large head ('washer head') screws specifically designed to racking equipment...
AND USE NYLON WASHERS TO PROTECT YOUR GEAR FROM 'RACK RASH'.
I don't know how much beautiful equipment I've seen on e-bay and other used equipment markets that looks great other than the area around the screw holes. Why not protect all your expensive gear from the start with just a couple of dollars worth of nylon washers?
You might also wanna get some "Rack Release" studs. They're a double threaded stud - one end is std. 10-32 and the other end is something larger (I have 2 types with different threads). You screw the 10-32 end into the rack and then mount your gear on the exposed stud and THEN you slip on your nylon washer (with a larger hole for the stud) and a knurled thumb-nut.
I use 2 at the bottom of all my HEAVY equipment so I don't have to fiddle with starting a damn screw while supporting a heavy piece of gear. I can actually rack or un-rack a 60# RTR BY MYSELF if I have to with these.
Sad thing is, the owner of the company suffered some kind of accident a year or so ago and they've basically closed up shop while he recovers. I haven't checked the website in 6 months or so, but the last time I did, they weren't selling any product.
Marker-tek has similar "Marker-studs" still in their catalog but their price (4/$10) is ASTRONOMICAL compared to Rack Release.