Billy,
I have used this stuff a few times and you asked for tips: First of all I can tell you to ditch, dump, disregard the directions on the website or can and you don't really need to use their speciality tools; I use a 4 & 6" whizz (for better control-messy stuff). I also use a 4" colorwash brush or a double loaded wide chip brush.
Expect splotchiness, streaks, uneven overlaps if you don't cross hatch them out.
This product takes more than you account for. Expect at least 2 to 3 coats depending on color and depth of applicaton.
Base coat in a similar color (eggshell)
It is a little more durable than suede, but that is not saying alot.
Keep the grandule paint stirred often.
cut in and cross hatch it all for for a more forgiving look.
Just can't imagine someone wanting to use this for "ceilings and walls"; not to mention all over .
Sounds like she wants a stone texture. There are way better products out here to achieve this kind of look. If you haven't used the RR I would definitely practice some first and remember practicing on just a small sample board is going to be nothing like working with the big picture of ceilings and walls.
Expect to see a lot of movement and variation with the finish. It just won't be a one smooth finish.
Like the others, I would either use a different stone product or use this for certain room applications.
Oh and forgot to mention, don't use your good cut in brushes for this. Nev-r , ev-r.