Well, I say a stud but it's actually 4, and that's just with the cross braces I put at the rear of the bench, I believe the existing structure that is there is secured as well to the studs.
Basically my test was to get on top of the bench with my body then jump on it. Couldn't feel it moving anywhere.
Also I forgot to mention I screwed the first layer of plywood down, then screwed the second layer from the bottom with 1 1/4" screws. Haven't drilled the grid for the tee nuts yet, plan on doing that when I get the press and can measure/plan a bit more carefully. I'm thinking a 2x4 grid of them spaced 6" apart should do the trick, but again I'm waiting on the press to really get a sense of how it's all going to come together. Figured I'd mount the press to a 2x8, if that gives me enough room on either side for securing the press.
Also, the top layer couldn't be recessed back like the first layer, so I had a bit of overhang, so my buddy suggested I run a skill saw along the edge to flush cut it, bad idea, haha. I ended up gouging and screwing up the front of my bench in a couple spots. Just ended up slapping some wood filler in there and doesn't look too bad. I figure I can give the face of it a coat of paint to hide my shame.