Thanks to your thread, I completed this mod yesterday. I figured I'd post pictures because I did it a bit differently.
I used a dremel tool with a metal cutting disc to carefully make incisions. Then I used a Milwaukee Sawzall to make the longer and deeper cuts.
My gas tank was half full. The dremel makes some small sparks but nothing to worry about. Using a sawzall works FANTASTIC... just make sure you're not a tard and keep the blade only tip deep on the cut so you don't nick those fuel lines.
As you can see, I cut a larger hole than most of you guys did. I figured I might need a bit more room down there and couldn't find any reason not to give myself a bigger hole besides having to cut through two layers of metal in a few places.
I have a donor truck (green 94 limited) that I used for a transmission swap into my white 94 limited. I cut a larger hole out of it's floor to use as a panel over the hole in the running one.
I used a hammer and chisel to break off the 2nd layer of metal along a couple of the edges. Then used some JB weld to fill in the holes from the spot welds. Then painted it with Duplicolor white wheel paint which is what I had on the shelf.
Added some weather stripping stuff around the edge.
Used some of those two-part push rivets that I tore off of somewhere on the donor truck. lol They hold the panel down rather tightly.