Welcome to the forum and this is the correct place for your question, but we are not too rigid on which Forum anyway.
Is the stand when in use, to be static? As in, not mounted on the rear of your car etc. If it is just for working on the bike in the shop or at the track, then without even calculating anything, I would say get the hacksaw and mig-welder out.
If there are going to be "bounce" loads, then maybe a few gussets would be a good idea at the tube connections.