Like you, I love using the flap wheel on the grinder to smooth all the sharp edges away. I also see in the next picture that you have another grinder with the thin cutting disc. I wish I had 2 grinders so I wouldn't have to constantly switch the discs from cut to sand.
So using the .035 mig...
try asking your questions on yesterdaystractors case forum. there will be guys who know a lot about your tractor there, maybe even gone thru what you're going thru