Re: Old dog learns new trick...Welding!
The Hobart Handler is an excelent little machine. I have one, 80s vintage that has served me well. I've used it to build the last four hot rods and countless other projects. I run it with a C-25 gas mix (CO2 and Argon) and I run .025 wire.
Practice and then a little more practice and you'll be welding like a pro in no time. For thin material, sheetmetal, take your time and do short spurts and don't try for long, continous beads. Start then let off the trigger for a moment leaving the wire welded in the puddle then pull the trigger again and go a short way again then stop. For thin stuff like fenders and other sheetmetal I usually only weld for two or three seconds before stopping and allow things to cool for two or three seconds then pull the trigger again.
Find some scrap metal or various thickness to practice on and just weld until you start to get a feel for how the metal flows when in a molten state.
It's very hard to tell someone how to weld. It would be easier to be there and watch then show you but there are some basics like keeping the tip clean, snipping the wire between welds so you're not starting with that little molten ball on the end of the wire, finding the proper amp and wire feed speed and so on.
Just keep practicing. I've seen your other work and I know you'll develope a technique that will work for you. Welding is somewhat of an art, and you're an artist. You'll do good.
Keep us posted on your progress.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"