splines are in - i made wide enough to leave about 3/4"" of space between the boards for the 'pin strips'
but... There was some warping. One one end the wood AND the epoxy appear to have pulled up about 1/8" in total. So while the glue for the spline cured I have put clamps on all along the edges. The opposite side had a bit, nothing I couldn't deal with, but as long as I'm clamping....
I've also found a local place here in small town that is making an angle iron frame for me underneath. I will use 1" screws every six inches to help correct current and prevent future warpages, plus it will be a cool design element. Having inset about 1.5" in from the edges.
So, today will be to flip and do semi-final trim to size, which should be about 44x81. The frame should be ready tomorrow so I can drill, paint and attach that. Then pour the epoxy in the spline channel for the underside. Since they are only about 3/8' deep should be set enough in 24 hours to flip - especially with the frame attached adding rigidity.
Legs ordered as well, will be 28" tall and wide, black powdercoated. The raw was only $20 less and since legs may take a beating more than the rest I thought I'd get factory finish. 2" tube to match the 2" L that is the underside frame.