Miller tends to make recommendations based on FILET welds - my "fix" for that, on both my previous transformer mm211 AND the newer mm211, is that
IF I use autoset at all, I'll "tell it" I'm welding about 1 gauge (like 16 ga. instead of the (real) 14 ga.) - Same on my mm252; I use one of those "slide rule" calculators Miller sells, and my starting point for 14 ga. will be to set it like I was welding 16 ga., that's usually real close.
Also, the lighter the gauge the more attention I pay to travel speed; I NEVER "drag" hard wire, and ALWAYS stay right at the front of (or a teeny bit ahead of) the puddle, so I KNOW I'm getting penetration and not just piling crap on top of crap.
All of the roof framing (24' square) over my 20' container is .120 wall 2" square tube welded that way; we just had winds a few days ago that were around 70 mph, and that roof and all the fiberglass is still right where I put it - so I'm thinkin' that whatever I'm doing must be OK :thumbsup: - probably 30% of that job was
done in place with the spoogun (needed the reach) - uphand, overhead, whatever; only had to grind out a couple "birdy-num-nums", and most of the "in place" stuff was done under a weld blanket (too windy)
I've known some weldors that, instead of turning it down, crank it 'WAY up and go like a scalded cat - I worked with one guy back in the '80's that'd crank a 250 class wire machine up to where you'd normally run for 3/8" steel, and weld 16 gauge

- he'd weld a
4 foot long OUTSIDE corner seam in about 2-3 SECONDS - a few of the other welders in that shop kept asking him how he did it, and he'd NEVER tell :laughing: Personally I doubt I could stay on the seam moving that fast,
then OR now
To my mind, if you don't improve EACH time you weld you're not doing it enough - I know my first welds after a week or more break are NOT as nice as the last ones - they're still plenty strong, but not quite as "pretty" as the later ones in any given session -
Well, supper's over; back to the shop - some of my fit up on the corner bracing on my modded HF crane are so weird I had to break out the mill to get the angles right - needed to "let in" 2" tube into 4" channel @ 45 degrees, bit tricky to get right with a side grinder

Well, back to the same ol' grind (er, I meant "mill") :laughing: ...Steve
Oh, and you DO need a TIG - maybe just get the new 215, still light weight and inverter, get wire tig AND stick (evil grin emoji goes here :=))