I got the Hobart 125 version of that. Mainly because the consumables are local to me at the local farm and fleet.
I’m really surprised how useful that little machine truly is. I don’t think I’d build a 14,000 tandem dump trailer with it. But for the most part it lets me do what I want to get done.
Ar plate is best welded with a bit of preheating not much about 200°F. Gusseting both sides of the tooth is not really necessary and in fact the confined contraction could lead to cracking.
It's a grapple bucket. I don't see cracking to be much of a concern if one side is wedled and let cool and then the other. You can peen or air hammer the welds, along with tight fitup and it should be fine. Gusseting both sides would be my suggestion based on how I have seen them used. Gussets can fold in compression.