A must read is Jim Colten's article right here, but hard to find using the BPL search function:
Silicone sealers, products intended for sealing, are not as good as the glues, like GE silicone glue, readily available on line.
I've used the glue with a roller, but no clamping as advised in the article, for attaching reinforcement patches to the corners and stress points on tent flies.
The patches were sewn over along the edges of the fly, but not along the circular edges of the patches several inches inside the perimater of the fly.
The patches have held up very well, and on test pieces, the unsewn edges will not peel away from the fly unless really pulled hard. Not a problem, IMO.
I found chain store Isopropyl alcohol and Bounty paper towels good for cleaning up as I went along. There was no problem sewing after the glue dried, easier actually.
There are no other adhesives I know of that work on silnylon.