emblethen, Emails were to and from Roadmaster. When I asked CW, I got a firm "I dunno." ;)
rekij71, no to measuring the straps. The only unit they have is boxed, and I wouldn't use a unit the manufacturer says wouldn't work anyway.
I responded to the last email with basically what I've said above, and to their credit, they said they'd pass my suggestion along to engineering. But I'll probably go with the Master Tow unit when I buy. Right now, I'm sort of hoping to find a used unit, and my next long trip isn't for a few months, so I'm in no rush.