After I saw the potential for Optimus-like characters made from the TF: Prime Ultramagnus toy mold, an idea clicked in my head: mod the shoulder's 5MM ports to work both inside and out, and use the Fansproject City Commander (KO) rocket packs to mimic the shoulder-ports from RID Scourge. The ports inside are the front and back ends of two different Iron Man guns (6" Hulkbuster 'Concept' armor series).
Also, instead of wrapping the leg-wheels around, I left them where they are - which I think helps emulate RID Sourge's leg design.
I disassembled the figure, sanded any problematic areas, and sprayed it with Tamiya gloss black as a basecoat. I'll start detailing it with Tamiya & Vallejo acrylics soon.
I actually painted a RID Scourge sword & the UM's windshield with Tamiya clear red & dipped each in Future Floor polish - but the result is so dark, it might as well be black. I'll have to just go for a solid metallic red / opaque windshield & sword instead.