Trying to get set up for kegging

So i've already purchased a 3 keg system.

http://www.midwestsupplies.com/brew-logic-triple-tap-draft-system-with-3-way-gas-manifold.html

I have a 7.0 cu chest freezer I will be building a collar for, I think I've seen enough plans to know what i'm doing there.

I'm planning on buying 3 Perlick Faucets 525SS and I will need 3 shanks.

My question is what size shanks do I need? Do I need a specific amount of extra beyond the size of my collar?

What else will I need?

 

I bought 1/4" shanks and the length is determined by the width of your collar that you put on your freezer.

I used a 2x6 to make a collar around the top of my freezer. I then placed a 1x8 piece of maple on the front and sides. The top of the 2x6 and 1x8 are flush with each other. The maple then allows for a support around front/sides of the freezer and you don't see the seam that the 2x6 makes. You have to drill through the 2x6 and 1x8 to insert the shank and that is a total of 2.25". I bought a 4" long faucet shank and it worked well.

 

I have a two inch thick collar and used 4" shanks, they're perfect. Any longer than 4" and it's going to be difficult getting the kegs in and out.