I thought I should post a final resolution.
Over the weekend I decided to test the left tank to check for leaks. No leaks found except at the inflatable balloon. I used the soapy water to clean the skins as well. I also discovered that the VAN fuel caps work, but are not fun to open.
With the left tank leak free (even with the temporary fuel sender gasket) I was really debating opening up a 5 inch hole in the baffle to fix the fuel sender travel issue or to add a fuel return filter.
The vent line only needs to be moved about 1/4 out of the way to fit the fuel float between the vent and the skin stiffener. I decided to take a round wooden rod poked through the fuel float hole and try to adjust the fuel vent line away from the stiffener. That line is very pliable and it was easy to nudge it away. I also checked to make the B Nut of the vent fitting was tight.
With the vent line moved, the float wire bent and adjusted, I am now reading min and max resistance readings when the float hits the top and bottom skins. Perfect!
Now, the return line fitting. Someone from this forum pointed me to the following site for an outside flange Bung that would not require a large access hole cut in the baffle. https://www.flyefii.com/products/acc...uel-tank-bung/
I could just drill the hole for the fitting and rivet holes, clean out the shavings that may gather inside the tank when drilling and then install with proseal and closed end rivets, (not the screws in the picture).
Then the last thing to do is proseal and screw the fuel sender in place.
As is usual with the build and my approach, there is usually an easy answer but it takes me some time to get there.