That's why I'm looking for similar to GE1 number 312A, because it's slow set, and moldable/smoothable for a while.
Scs1200-fast set, cures 5-7 days, highest strength. Pricy.
Dow 795-slow set, cures 7-21 days, not as strong. Not so pricy.
Rtv 108-somewhere in the middle of the other 2 in all qualities. Some say it's the "ideal" choice. Also pricy.
The technical specifications for each of these adhesives can be found via quick Google search if you'd like to look over the data yourself. The key is finding what you can build with the best. I started with Dow 795 since it was so workable but have branched out to other quicker sets as I improved my building skills. Even though it doesn't spec out as strong as the others it is still quite strong. Here is a 200g rimless with dow795 that has ran continuously for 2 years with turbulent flow and minimal safety factor (5/8" side and bottom seams).
And here's a 100g sump I built out of scrap glass this past weekend for a new setup.
If I had it to do over (and i might), I would use a higher strength silicone for the big rimless tank and use perfectly cut and polished glass. The dow795 is perfectly fine for smaller projects like the sump that I cut up in my backyard.
I've never worked with rtv108 but a lot of people swear by it. Seems like a perfect medium of qualities just by reading the spec sheet though.
What size tank(s) are you building?