Powdered sugar will make it stick much quicker in my experience. It has sugar in it and that is just a recipe for disaster IMHO. Using straight corn starch is nothing like using PS and I was amazed at the difference when I switched. When I say it sticks, it's not in the way most are thinking. It's more that it stays tacky and doesn't glide over the counter top like it does when I use corn starch. So when I roll it I have to lift it a lot and I find that annoying... then you have the tackyness when you want to smooth it on your cake too and your smoothers want to get caught up on it and not glide over it nice and smooth. I suppose it is all about what you are used to working with. There is no right or wrong way... only what works for you. Not knocking it if it works for you, but I prefer not to use the crisco or muss with the vinyl mats when it take seconds to just do the way that works for me.
You do have to work fast. SI dries out quicker than most fondants I have used. I notice it on dummies because they aren't chilled like the actual cakes I make which are completely chilled. The mild condensation battles the elephant skin nicely.