Fuel Cell- Where to mount it

picked this up at a swap meet,
thought the 17 gallon (running E-85)
would be better than a 10 gallon I have

30" x 17" x 7 "


want to be able to get to the spare tire if needed.

here I can still fill the cell





have thought to move it forward, for more trunk space
In front of the cell would be wasted space



But, then i would have to put the fuel fill assembly in the filler panel
and a short tube to the top of the cell, in order to add fuel



or move it to the rear,maybe sink it into the spare tire well ????
mount the spare tire forward



What would work best ?

Don't want to use a stock tank cause
The girdle on the Dana, will hit the stock tank
plus need the space for the exhaust pipes