brake booster push rod length

I have a 1995 Silverado. Does anyone have any specs on the brake booster push rod length from the flange to the end of the push rod? I don't want to pay $45 for a height gage to use one time.

a thin steel rule should work, the kind you see in people's front pockets
it has a T-head that slides

I actually used depth micrometers and a socket to hold the push rod in the master cylinder piston pocket so I could check the stack up. I then used the depth micrometer to check the static postion of the push rod in the booster from the flange mount surface. After calculations, it appears to have about .025/inch clearance. But I need to know if that is within spec.