Tech D, Wedi has their own. The sealant is very sticky and like rubber when dry. The sealant gets smoothed with a putty knife right after it's applied. I made the mistake after waiting too long to smooth one seam and it looked very rough. I was able to shave down some thicker portions of sealant with a razor knife. And in another spot that was rather high with sealant, I wacked it with a hammer and the foam compressed but didn't open the sealed joint. Any tipped washers also got a slight tap with a hammer to level them before the sealant was applied. Their corner trowel is a must have, too.
BTW, I used the sealant to attach a wayward mosiac on another job. It dries fairly quick and has a thick consistancy to support the small tile. It might be a good product to squirt into any holes (theresholds,towel bars) that are in the shower, too.