One of the main tips I can give everyone for working with RBC is to use cornstarch when rolling it out. It works so much better than powdered sugar to me. I think, adding more powdered sugar can be done while in the mixing process...so instead of 2 pounds, maybe 2 1/2 or 3.
I do have to say, working with rolled buttercream IS way faster than outlining and flooding. And I like the RBC taste with cookies. I flavor mine with clear vanilla and creme bouquet. I roll it out, cut the shapes, and immediately transfer to a wax paper-lined cookie sheet to put in the freezer. Then what I do is bake the cookies, and as soon as they come out of the oven, put the RBC shapes on the cookies. The warmth of the cookie adheres the RBC...this way you don't have to go back and apply with corn syrup or RI.
Here is one of the problem I have had with RBC...when I detail with RI, the detailing comes off during packaging (not all of it, but certain parts). I figure this is due to the grease. So what I will try next time, is let the cookies sit for a day with the RBC to dry out, then detail. Anyone else run into this problem? Any tips?