OK I'll give this on a shot.
1) I used metal plumbers tape. The stuff with all the holes and comes in rolls. There are holes in the floor pan for the mounting straps. Bolt down one end, put in the tank and run the tape over the tank down to the other hole. Kind of hard to get the second bolt through the tape and into the hole, but that the way I did it.
2)I used some rubber pad I had. If you want the tar paper stuff, just use some 30 lb roofing. This can be used for your anti-sqeek gaskets for the fenders nad running boards.
3)You can run the wire through the cab but remember you have to be able to take out the floor to get to the battery etc. How will you hide the wire along the edge of the door?
4)Yes
5)That should work. I don't have a shut-off on mine.
6)I don't remember (getting old I guess) I think 30 ohm.
7)Yes, Mine is.
8) The stock fuel cap is vented. If you get a repro. be sure to get one for a 41-46.
Hope this helps.
George