Fuel System Q's

[Chris4x4Gill2]

I am doing a rear fuel cell conversion. I am using a FCG cell.

I need some educating on the best way to run my lines.

It has a stock mechanical fuel pump with return. My plan was to tie the new lines into the hard lines under the cab and then use the stock lines to the pump. This would consist of a feed line and a return line.

The cell has two fittings on it that I planned on using, one for the return, one for the feed.

Now as I'm looking at pictures, I see that alott of peopel with the same tanks are not using a return line at the cell and using the 2nd fitting as a vent. If thats the case, how/where should the retunr line be ran? does it "T" into the feed line? This doesnt sound right to me, but I see it having a vacuume problem if its not vented????

PS, I know I neeed to vent the filler neck, but I havent got to that yet