The skinny on fix a flat is that it works by centrifugal force, so with a standard quart application, you have to shift and rotate the goo around and around in the tube to make sure you hit the leak, however small. It then dries semi soft and supposedly doesn't allow for multiple inflate/ deflate scenarios...meaning...if the tube collapses in deflation, the stuff sticks to it self inside the tube.More than one quart may be needed for the size of the tubes.....
The Tube- Seal seems to be a different chemistry, and does allow for over and over inflation. Would be interested to know...I have a small inter tube leak, that requires a top off once or twice a trip when out on the water, I do know that when I inflate with the 12 v pump, I am going to see a pressure drop about 20 minute in in the water..( Hot high pressure air...cooler water temp etc etc). No big. the boston valve doesn't leak when the top cover is removed and top off is easy with the hand pump. I also see a drop in pressure as the day usually hot,moves into evening, and /or the wind shifts or starts up.....also due to the change in barometric pressure. Sooo.. I just expect to top off a few times in the course of a 10 hour fishing day.
I wonder, off the cuff, if the fix -a -flat, with its ability to remain soft, if a small layer of the fix a flat were applied around the threads of the boston valve when inflating,( air leak assumed coming from valve and/or threads)that at the end of the day you could wipe off the threads( it is a latex emulsion) and then re-apply next time you set the mariner up. Fix-a-flat is 7.95 /quart...if just used on the threads would last a long long time for very little money.