The toolbox tank probably does matter, however get this fuel controller.
Auto Fuel Controller - The Fuelbox
Its the best I have found, and LOVE it. Way better then gravity feeds, no worry about overflows. Their toolbox combos seem great too, so you could just get the entire thing from them.
The other option you have is to just replace your fuel tank. There is plenty of room underneath for a larger fuel tank. Thats what I did on my ford. However my new RAM didn't have the same amount of room, so went with the combo box instead.