I'm doing a dry start right now in a bowl with 1/2 carpet being flame moss. It seems to be doing decently and attached itself firmly to my substrate, I'll be filling in another 2-3 weeks and we'll see.
We made about half a 40 breeder into a xmas moss hill - we used paper clips with thread between them to hold the moss down until it attached...you can also just open a paper clip up straight to hold a pretty large chunk down. You should try it, worked really well for us. You can check out my journal if you're interested.