3rd time might be the charm ?

 Well, here's to hoping that I am capable of learning.  Specifically, this is the 3rd time I've sealed the fuel level senders & inboard access plate.   I have learned one thing -- I neither like nor am skilled with working with Proseal.  (BTW, Proseal is a brand name and I'm using generic products but will continue to abuse the name because I'm lazy.)

I'm pretty sure the access plates are not an issue because they are horizontal and straightforward.  The fuel senders are oriented vertically, so gravity is not my friend.  They also have a wrinkle in the installation:  one screw is fitted with an internal tooth washer, an electrical spade and a second internal tooth washer.  This stack-up is designed to have the angled teeth of the washers cut through the layer of sealant and ensure a good electrical connection from the tank itself to the electrical spade that will later be used to measure the fuel level.

On the previous installations, I had a lot of trouble holding the spade such that it didn't fall into the goop and I ended up making & breaking the connection of the sender's plate and the tank.  I suspect that didn't help the smooth, careful and uniform distribution of the sealant.

Rubber band as 3rd hand

I used a small rubber band to hold tension on the spade connector and trusted that the 'top' washer wouldn't go anywhere if I treated the arrangement with any delicacy.   In this photo, the connector is on backwards and would have dug into the side of the tank, but I installed it correctly after this dry run.

Sealant under electrical hardware

I smeared a small dab of sealant under the location of the hardware, then inserted everything and held it with the rubber band.

Smeared Sealant prior to installation

I then applied a bead around both the tank and the sender and smeared the beads into a relatively uniform bed.   Finally, I used one of my favorite tricks of inserting awls through two of the holes in the mounting plate and then into the corresponding holes in the tank and sliding the fuel gauge sender along the awls and into position.  I had a screwdriver at the ready to manipulate the screw (that was holding still because it was held by the rubber band) into its nut plate, then quickly inserted another screw into its nut plate. With two screws to hold orientation, the awls came out and the remaining screws were started, then evenly tightened.

Mounted Fuel Level Sender

As you can see in the final picture, there's a nice bead of sealant oozing out around the entire circumference.   It's a little thin at 12:30, but there is visible sealant. :)    BTW, I did both tanks at the same time, but only published pictures of one side.

I think the next time I'll have time to do a leak check is next Thursday, the 20th.   Fingers crossed!