You did a good job. Looks well done. Only thing I'd do different is the small BEC wires on the battery input, they look like you could have got them more "into" the solder. But if they are well connected, it shouldbe fine.
I know how the heatsink on that MM can make it kinda hard to de-solder the original wires.... I have done this mod many many times. Though I never thought about charging people for
just playin
