Made mine from two sections of scrap aluminum that were 1 1/2" x 1" angle, about .090" thick and a little over 3" long. I don't recall what the scrap had been part of, I just tend to keep a supply of scrap in the garage that looks like it might be a handy size and shape.
I drilled the side rail of my Summit climber platform and bolted the holder to the underside with two 1/4" bolts, washers top and bottom, through vertical holes and through the double thickness of the 1" side of the aluminum, to form a squared-off inverted "U" below the rail.
The two pegs to actually hold the bow I made from some scraps of aluminum and carbon arrows. I made them originally from some 2219 aluminum pieces, three inches long, but they seemed kind of flimsy to trust, so I added some carbon arrow pieces inside the aluminum ones to assure the strength needed. The aluminum parts didn't fail, just seemed flexible enough to make me doubtful of their durability, so the reinforcement was more for added security than proven need. Hard to be specific about the strength requirements, since different bows will dictate different peg locations, with different resulting leverage of the bow's weight on the pegs. The basics should apply to a variety of bows, and the pegs would be easy to reinforce further if needed.
I tested with a clamped-on wooden block to find the best location for the pegs. That will vary depending on your bow and preference as to the amount of lean you desire to build in. The location I ended up with was with the pegs about 13/16" apart center to center horizontally, and the rear peg about 11/32" higher. That seemed to get the amount of lean into the bow that was best for my Browning single cam (40" ATA) when I made the holder, and still worked well with my Mathews LX (35" ATA), which is an older model with less parallel limbs than the newer bows. Those dimensions will almost surely need to be adjusted to fit the more current models.
I attached the pegs to the holder by just drilling the holes for them in the locations determined by the testing, and drilling the pegs for small cotter pins on each side of the holder in each peg.
I've been very happy with the performance of the holder. Thought it might need to be wrapped in camo tape or some such to prevent the bow from slipping sideways on a windy day or and uneven setup, but that never proved necessary, so I never added the tape.
The holes through the stand should be VERTICAL ones, to minimize the effect on the strength of the side rail. They will almost certainly void the warranty as well, if that's of any concern.
Sounds like you might be interested in a few of them, so I should mention that 1" x 1" aluminum angle would likely be big enough to do the job, depending on your peg locations, and square tubing or "C" channel would be every bit as good if you have any available.
I had thought that the pegs might stick out enough to make me want to remove them until I got to the tree, but they never seemed to get in the way or catch on brush at all in my usage, so I never removed them.
The nuts and bolts were the only purchased items and the weight is nearly as minimal as the cost.
