Mike, I have fabricated probobly 90% of our stands out of 1" or 1-1/4" tubing. I recommend you use a shooting rail. I fabricated ours out of 3/4" conduit. I simple put two 90-degree bends on them to form a wide "U" shape, then put a kick on each side to put the rail out a bit from the ladder portion to allow you to climbonto the platform.

I attach therails by bolting two conduit clamps (1 @ 3/4" and 1@ 1" or 1-1/4") and attaching them to the ladder. A piece of pipe insulation taped on as a cover and you have a steady gun rest. No more than $10 each.

If you don't have a tubular ladder, say maybe 2 X 4's then just pound the bottoms of the rail risers flat and drill some holes and nail it on.