input wanted for installing dual tanks

[rmmurphy]

I have a 68 c10 swb stepper. I was looking at the choke delete in my dash thinking i should put something there. Here is my idea. If i put a blazer tank between the rails and do the side marker fuel filler, why couldn't I keep my tank in the cab and get the valve and other misc. from a 73-87 that had dual tanks
. And use a wiper switch where the choke delete was to swap between the 2 tanks?? low position for 1 tank and high for the other. Any input would be appreicated before i start collecting parts i won't use. THANKS