Sign up for the free beersmith software. You can enter your recipe and then scale it to anything you want and it will adjust the ingredient amounts for you. Though in your case just doubling is easy. I like to take a lot of 5 gallon recipes and scale them to 6 gallons to ensure I get 5 gallons in my keg after loss to trub, racking etc.
Tap#1 = Beer
Tap#2 = Beer
THey change to often to keep up with the Sig.