I'm setting up a 400 yd. range and would like some of your ideas on bench design.  I'm gonna start with a 4'x8' piece of plywood, and i will have it anchored securely on concrete posts, where my ideas run out is on the design of the bench top.  Shape, cutouts, etc.  I would like it to have 2 shooting positions.  Also i need suggestions on seat design.  I'd like a design that can be adjusted for height and distance from the bench.  If you have any suggestions, maybe from ranges u use, I'd appreciate it.  

Thanks  
AL

Big Al I built a bench out of 4.5" sch 40 pipe and 2x4's for the top.  It has three legs that rest on top of the ground so it is somewhat portable and has two cutouts (T shaped) to accomodate right and left handers. It is very stable.  I would recommend your chairs be independant of the bench so body movement does not effect the bench no matter how braced or heavy your bench is. It turned out larger than I originally wanted but then I realized the extra space was handy.  Drinks, ammo, other rifles, spot scopes, cronographs all made me realise that if its a permanant bench you can never have too much table top area.    

Make it usable for prone shooting, so you don't have to get down on the ground.

I have been wanting to build a new one myself. Lately I have been toying with the idea of making mine from poured concrete. All a person would need to do is form it all up, making the seat and bench one piece. It would be weatherproof, indestructible, and have absolutely no movement whatsoever.