Just a couple tips for folks who find someone to weld the base for them.
My whole reason for posting this is ericspaw's post about "close enough is not quite close enough"
(If you're welding it yourself you probably already know all this so disregard it, but I know some folks will seek out a buddy to weld it for them and might not know this stuff.... so watch out for it
)
Personally I would weld something like this up with solid wire (wirefeed) or TIG.
If your buddy is going to stick weld it, then ask him to use a low hydrogen rod like 7018. There's no need for a deep penetrating rod like 6010, and unless he's real good with it, it won't look as nice. 7018 will lay a very pretty and uniform bead.
If he tries to just weld up the whole length of one side first, then he's not accounting for warpage. Ideally you'd tack the ends, then run your welds down the sides. If he's really good, he'll probably stitch weld it and be able to run his stops/starts smooth enough that it looks like a continuous weld.
An experienced welder could account for warping by simply offsetting the upright before welding, but with the tab that sits down into the base plate I don't think that's possible.
A good weld could make something like this even more solid... a poor one could screw it up.