I checked out the website, looks like a pretty simple and sturdy build on the platform. The legs are another story, the lag bolts scare me. I've dealt with them on homebuilt stands and after a few sits, just the climbing and normal shuffling around in the stand while sitting causes most lag bolts to loosen over time. It usually doesn't take long either. A through-bolted connection would be far better in those leg pockets. Simple and easy to construct if you have a welder. Really just 1 20' length of angle iron and a half sheet of expanded metal for the main platform and the leg pockets could easily be fabricated and welded from small pieces of 3/16" steel plate with no forming or bending needed. One could cut the railing tubes at a 45 degree miter to weld the corners instead of having the radius bent corners. A guy with access to the materials could make this with nothing more than a good right angle grinding machine with a cut-off wheel, a few normal shop tools, and a welder. Having the proper tools would make for quicker work, of course, but still a very simple project for someone with a welder.