I would really consider changing your tire selection to a 275/30/24. The difference it price is well worth it and the tire will sit more flush on the rim instead of being much wider than the wheel like the 295/30/24's.
Also the thing about 2 5 gallon tanks, I run 1 5 gallon tank on my family's full size and have no complaints. The air is always there and takes me less than 2 minutes for my tank to be filled. Plus I get to have the tank, compressors, valves, and 2 battery's all under my short bed bed floor. If you plan to play with your switches a ton, I guess you want more air, but damn man, we aren't mini truckers.