Quick CAD sketch while I'm on a work Teams call . . .I'm sorry but do you have an example I don't quite follow. (Sorry I'm still new and learning)
About the only times I used MIG as opposed to stick was welding up chutes and hoppers. Most of these we would fully weld vertically down on the outside. The insides were just stitched unless a 'dead pocket' was an internal feature of the chute; that area was usually fully welded as well. Your material looks a lot thinner but I think that technique would work well.If I was welding that from scratch, I would tack it, clamp the piece in a vice vertically and apply the weld vertical down which will give a nice bead with less clean up.
You need to be quick and keep in front of the weld but it would work well for that.