Gas vs propane, stock tank vs fuel cell vs cylinder

So I'm at that point of my project, I got just about enough of the electrical system working to get the car running and now I have to decide if I'm going to send the carb to be rebuilt or invest in getting the fuel system converted to propane.

I bought the car with no gas tank but their is currently one hidden in a local junk yard in decent shape. Down side is the sending unit maybe in less than ideal condition and the fuel filler pipe seal isn't salvageable.

I have an 8-10 Gal fuel cell that I got for a 4x4 Toyota but it really doesn't work in the trunk and I'm not sure that I'm ready to chop up such healthy sheet metal.

Then there is the propane option... And this is the option I have the least experience with and least amount of resources for. If I go propane, turbo charging will be part of the plan.

I should point out it's a 75 swinger /6.
What say you the experienced of FABO?