I have a 500 gal propane tank with two 3/4" fittings (1 of which is a dip tube), one 1" fitting, and two 1-1/4 fittings on the top of the tank. There is also one 1-1/4 fitting on the bottom of the tank. If I need two supplys and 2 returns, how should I utilize these fittings the best way? I would asume I will use the fitting at the bottom of the tank as a drain. Any input would be appeciated.