The cart design looks really nice. I was wondering though, are you not concerned about the lack of air space behind the welders for air circulation? Page 19 of the 211 manual specifies 18" of space behind and in front for air flow. I believe the space requirement spec is the same for the Dynasty too, I know it is the same for my MM252.
It mentions the air space on page 17 of the Dynasty 200 manual.
I did think about that before I started building, but I am not too worried as I am a home garage hobbyist and will probably never run either machine full load or even close during my normal use, and if I do, I could always pull the machine forward to give it more area.