2mm wall is fine to be welded. Of course, MIG or TIG is easier than stick.

Project One andProject II: Hexemhad a frame of 40*40*2 box section, with -if possible- the cross section so the most impact forces were handled with the 40mm side in the same line. In Project One I made the mistake to weld the frame, and then getting the fun job to drill holes in a completed frame because it was overweight.

In Project II we predrilled the box section with 22mm holes with 32mm between centers .
33 holes the meter , giving us 400 grams gain on 1.7 kg. A lot easier working then drilling the frame after welding.