Thanks for all of the advice. A 220 plug is definitely in the works, as well as some electrical outlet upgrades. I do have a heavy 12 gauge extension cord, but I thought I was getting some losses from that too, so I don't use it. I will from now on.
My welds are acceptable, they seem strong and take the abuse of the plow very well. Not real pretty and far from a professional job, but I'll take the win. I have welded four pieces of angle to a blank skidsteer plate, and also cut the plow A frame and shortened it. I placed a new piece of angle as the cross piece and welded the old mounting ears to that. Non of those welds broke.
In my head, I was thinking the 0.030 wire would slide better due to being a looser fit in the cable, but I think I'll try a heavier wire. The drive roller is knurled.