Which Sikaflex?

I'm trying to track down a small leak somewhere round the roof of our 17 yr old Rapido pop-top. I believe Sikaflex 512 is the stuff to use, but there are so many Sikaflex varieties - is this the right one, please?

So far I've tried strategically applying water from the spout of a watering can, working my way up gradually, and waiting to see which spot produces the water inside where it shouldn't be. (Luckily it seems to drain away quickly and I think it's vanishing into the locker space rather than being absorbed into the fabric, but I still want rid of it!) Latest tests consisted of putting gaffer tape on a suspect seam, then emptying a bucket over the top. So far I'm encouraged.... but I've been there before, thinking it was sorted, until the next really torrential rain proved me wrong, though I reckon I've reduced it!

Meanwhile it would be good to be sure I'm buying the right stuff to put in place of the gaffer tape.

Thanks.