BTW last time I did mine it was on a set of 10 ton jackstands. Not that hard, just hard enough you do not want to do twice so only buy a quality pump. Also I always replace the sock and the filter.
(Once replaced the clutch on a Buick GS on an oak tree root. Needs must.
But first check the electrics, may not be the pump atol.
Fuel gauge also bad sounds like a wiring problem (pump and sender are together). Think I might start by disconnecting the connector and checking the wiring. What was the ohms reading on the green connector ?
This is the pump I purchased. There is no drop in assembly unless you want to pay more. Easy to change and my wiring didn't need modified even though extra parts were included. Amazon.com: Delphi FE0039 Electric Fuel Pump Motor : Automotive
As mentioned my back support is a seat tilted back 30-40 degrees. Less and my back hurts. My speech is mostly mid-atlantic bland having grown up in Maryland. In London was once asked if a BBC announcer.