This is the only way I apply my product(in the shower, that is). I haven't tried combing/brushing the product in yet(I prefer raking/scrunching it), but I always apply my styling products while in the shower. I can imagine that it would work really well using a paddle brush since it would help distribute the product better, and aid in curl clumping.
And it does help to have a mirror. I have one of those shower radios that has a mirror attached. Comes in handy.
Let us know how it turns out for you, Gabby.