Franky,
All of our outdoor benches(we have 16) at Salem are the same height. We started out at 32" but raised them to 34" because we have quite a few tall shooters that were uncomfortable at the lower height. It's easier for short guys like me to raise my stool that it is for them to bend over with their stools lowered as far as they would go.
One of the best Rimfire BR shooters in the country, Gary Mitchell, shoots from a wheelchair off the same benches that everyone else uses. I don't remember if he uses some kind of platform.
And I'll second what Pete said, there really isn't a standard height. As you've probably read on the forum, people are shooting off everything from folding plastic tables to solid concrete benches.
Are you thinking of building a range in Plainville?! If so, I can pretty much guarantee 2 shooters from NY at most of your matches!
Todd