I'm working on some little projects (moving outlet locations in my shop and building braces to hang them on the underside of the c-purlin around the shop).

Previously the shop owner had welded the outlets to the top of the c-purlin, but I'd rather them be on the underside so I can set stuff on top of the purlin.

So I'm bending 3" wide 1/8" thick strap the weld to the underside of the purlin and then I will bolt the new water tight receptacles with covers to the strap.
In addition to getting the outlets the way I want them, this is giving me the opportunity use my new Millermatic 252 and become more familiar with Mig welding with shielding gas. All I had ever used with my MM140 was flux core.

The question I'm having is with bead height. It looks like the majority of the weld it pretty tall in height so I'm wonder what ways (techniques) to use to smooth it out?

I'm using the recommended Miller settings for 1/8" (17.4V and I think 230ipm and shielding gas (75% argon 25% Co2) at ~24cfh.
I have the material butted flush with basically no gap.

I did have a few pieces where there were gaps and the weld flattened out more until it started to (key hole I guess its called) basically burn through which was fine until I got to far ahead and the wire just poked through the hole without touching material causing my arc to stop. Then I had to restart.

So I'm wondering what would be the best way to setup the material for Mig?

I just got the material from the steel supplier and it was all kept indoors so I didn't bother grinding the material where I was welding before hand.
How important is removing the mill scale? I didn't have porosity.
I just need to get use to watching the puddle looking around the big mig nozzle so I can weld where it is suppose to go. Also getting use to a new fixed shade #10 I have in a new jackson hood I bought. I like the headgear in the new jackson better than my +10 year old jackson hood I have. I have found keeping the gun perpendicular with the material helps to flatten out the weld some.