Sure you can roll it on with a foam roller and tip out the bubbles with a high quality brush but it's never going to look as nice as if you sprayed it on. Everyone has a different idea of how hard or how fast to apply something with a roller or brush so you'll have to experiment to find what works best for you. Some people like having the paint a little thick, others like it thinner. The speed and pressure that you roll on the paint and how wet the roller is when you put it on the surface you're painting will also make a difference.
The concept is to roll out the paint in one direction only. Keep rolling until you have a nice even coverage. Only try to work a few square feet at a time. Rolling produces bubbles. To remove the majority of the larger bubbles you need to take a super high quality paint brush about 3-4" wide and lightly pull it across the paint to "tip out" the air bubbles. Only pull it in one direction and only pull it across the surface once. There will be tiny bubbles left but the paint should flow out and the bubbles will go away. After about 15-20 minutes you will need to drop the brush in a bucket of water for clean up later and take another clean brush and keep working. Tipping out the air bubbles will load up the clean dry brush and it's better to have a few of them to rotate through than to stop, clean, dry, and start over.
I've been told that the 5" wide foam rollers with a sharp edge are better than the ones with a rounded edge.
Do not try to put all the paint on and achieve full color saturation in one application. Expect to apply 2 or 3 coats. Let the paint tack up real good between coats or when you go back over it with the roller you can lift off what you previously laid down.
Rolling EkoFill on fabric tends to leave a rolled texture if you do not take a dry roller and go over the semi wet EkoFill just before it's dry. The second roller is effectively removing the texture so you don't have to sand as much. after the 2nd rolled on coat you must sand the EkoFill smooth other wise the texture is only going to get bigger and bigger. Use 320 open coat sand paper and red scotch-brite.
Rolling paint always will leave some texture behind.