Actually I bought the very Miller all-in-one you are talking about, only 29 lbs without wire and comes with a carry strap. So far I have set it to pretty thin but I think I am tacking too long and need to do a bit quicker. The auto settings have been awesome for welding tabs for example, if I futz with the settings, it gets worse. Use what it auto selects and I am fine.
The next trick I have heard to try is using the 110V setup for thin stuff - leaving is set on the 220V is supposedly a bit much.
Pics of the new wheels on the Vette and then I mocked up the left rear to measure out suspension parts to keep ordering. What I like about using wheels with a lot of backspace is then when the car is on the ground it looks a bit more of a sleeper - people would likely assume stock-ish widths at first glance and just think the car is a bit of a classic upgrade... until you get down and look at the width of the tires
Also seeing how the 295 and the 335 fits a bit narrow IMO is promising as well for running a 320/355 race slick setup down the road.