I'm looking for some help with plans/designs/ideas for the construction of a shooting bench for a private range. I intend to use the bench as a sighting-in bench and a medium range target bench (300 yd). My requirements are 1) ambidextrous 2) top constructed of concrete. Beyond that I am open to any and all ideas and suggestions. Comments about what you like and don't like about various benches you've shot from. Any help will be greatly appreciated.