I ordered the 12x24. Got it today and it's actually a 16x28. I guess the 4' overhang is total, not per side. I doubt it'll be big enough with my t-top but should work fine for my other V. Guess I'll order a bigger one for the Green boat.
It's a lot thinner than I imagine as well but for the price I guess I can't be surprised. Be curious to see how it holds up to the little bit of snow we see here. We'd be lucky to get 6" at one time here so shouldn't have to be too load bearing.