Don't pull the tank!
Is it the sender, or the access plate?
I just did this on my 6A. You can remove the sender from the root. You wouldn't think so, but it was quite easy. Plenty of room.
I purchased a right angle ratcheting screw driver on Amazon:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
The screws came out very easily (I did make a little "button" to put over the back of the bit so I could keep pressure on the screw while extracting, but it probably wasn't necessary).
You can remove the whole sender (after removing the electrical wire, of course) and clean it up on the bench.
It it is the access plate, you can then remove that.
I was dreading it, but it was no harder than changing the oil. Mixed up the little proseal kit, put it back in with socket-head cap screws, and... no leaks!
(I am sweating the other one though, it has a flop tube and the sender on the rear baffle...)