When welding with a MIG you do NOT weld in beads. You weld a seem shut with countless superhot tack welds.
For as long as I've been on this site, you are the only other person, besides myself, that's ever suggested this. Back in my day that's how we did it and you don't even need a face shield, just wear a welding glove on your left hand, point the wire where you want the tack, cup the tip with your gloved hand, pull the trigger for a second and repeat.
HERE'S a picture of a Plymouth Duster prototype I did back in the early 70s.
Luckily, I moved on to a TIG and never looked back. Did all the welding on my truck with
THIS remarkably good TIG machine that only set me back $700... an excellent price for TIG.
For
HEAT CONTROL nothing even comes close to a TIG.
As for the cleco method of holding parts together, it works well when parts fit perfectly but sometimes you just need a little extra oomph so I use
ALUMINUM BAR STOCK pieces and sheetmetal screws.
Of course, you can always take your time and get some parts to
FIT TIGHT and they don't need any clamping.