I typically use a pretty fluffy poly batt, I'm thinking the problem is from too heavy a spray. You shouldn't be able to see the spray or feel cold or wet spots, those are all signs of too much. About the only thing I've found to do with too much spray is keep it out and open... may take up to a week to dissipate enough to smooth out.
Go in small sections. I typically go about 1 foot each pass from the center to one end. I use my 6x24" ruler as a reach extension. Then I'd turn it around and do the other half, still only a foot or so at a time. Once I got the backing onto the batting, I'd turn the whole thing over and put on the top as carefully as possible, but it seemed like I always had to do the back again. For the re-smoothing I'd typically work from the corners toward the middle. The front rarely needed a re-smoothing.
Use as big a work surface as you can -- for years I used my queen sized bed (with four posters) which made it challenging to do large project. I took off the beddings and covered it with heavy duty kraft (brown) paper. Later I got a ping pong table and clamps which was a better height and really sped up the process.