A, B, C, and D are in order of how I'd load them. Not sure if I'd get to 4, but this exercise will help answer if that's even attainable. Also I am guessing 150 as my starting tongue weight, assuming 1 propane tank and 1 battery on the tongue (which could change, if necessary) I'm going to start with the following guesses:

TWMa = .61

TWMb = .72

TWMc = -.35

TWMd = .80

I could also estimate some bike weight variables..

Bike A = 240 my 250 XCF-w

Bike B = 110 Gavin's 50

Bike C = 185 Gavin's 80, when Violet gets his 50

Bike D = 250 My 450, when MIchele gets my 250

Putting all of that into a calculator, it seems very possible to stay within my receiver hitch's limit of 650 pounds tongue weight. My current slide-in ball thing says 500 pounds though, that's a better target anyway. Here's a calculator to see how this works out.