A week or two ago I posted about a load cell with a toasted gauge. I stuck another gauge on it, but of course this one was calibrated in psi not pounds, and I didn't know the area of the piston so I posted asking for ideas.
Today a local guy with a load cell let me run up a load on mine while reading the same load off of his. A-HA! Piston area is 10 square inches, pounds = psi/10.
Borrowing the load cell was the best answer, although I liked the inviting 10 guys over and loading them onto the thing too. :-)