i breed mollies to feed my marine betta, and I keep them at about 23 ppt; they seem to to better than at 35 ppt, where some will not live long. I just did a drip acclimation over a period of about 3-4 hours and none died.
From 23 ppt straight to the tank at 35 ppt, the fry have no problems living until my fish finds them.
Hope that helps....if you want more info on my setup, I can show you that (if you are wanting to breed them); it's super easy, and I get 25 or so, 1/4" - 1/2" fry every week to feed....all for $20 and about 2 min. a day.