The underside of the frame have gotten some paint and the epoxy experiment has begun :D
I framed the x rails with wood and sealed it to the steel with latex. Then I glued strips of masonit to get the right width of epoxy channel. 40mm wide for 20mm wide rails and 50mm wide bridge at the middle of the rails. Have just brushed on a small layer of epoxy to really get it tight with no leaks. Big pour will happen tonight or tomorrow!