Another Ahab - based on my experience with the tents the shoe goo will hold. It holds your shoes together doesn't it... ha ha. Look at it this way, nothing to lose by trying. It's really strong though, if applied to specification and you get a good strip down as wide as those seams are. Remember people crank down pretty hard on the tents too at the corner stakes, and the wind puts a TON of tension on everything.
If they are going to be re-sewn it is worthwhile to use a better thread than they did. I think someone got cheap somewhere (which is really saying something because the last time I bought thread, I bought like literally 19 miles of it for thirty bucks, the good stuff) because the thread shouldn't be failing before the material UV rots out. But I agree that's what we see here with the tarps, mine is the same way.
Yes, Juki in this context is a large industrial machine. They make many of them, but the one for this is the one I have, the 1541. I use it to sew all manner of things, but mostly I sew straps and rigging and bags, equipment and tool rolls, covers, stuff like that. Manly sewing I like to joke.