I have been doing the bedliner mod on my rims for the past couple of days and had the same exact problem.
The issue is that the cans are too cold. When they are cold they spit out big old nasty globs of the liner that is far too thick and takes forever to try, as you described, plus it makes it difficult to get a nice even coating. I thought I had mine warmed up enough, and nearly destroyed my first rim because of it.
What I ended up doing is sitting the cans in a large bowl or cup of circulating hot water for a good 10-15 minutes, longer if you want, before you use it. I just sit a big cup under my tap and turn on the hot water and let it sit.
After you do that, and shake it up really well, the spray comes out extremely fine, and is perfect for the rims. So yeah, warm them up really well and you'll be happy with it. And as far as drying, just make sure you are in a warm-ish place. I was set up in my garage with a heater blowing directly on the wheel, and the layers dried fully in 15ish minutes. Just be sure you aren't putting too much on at one time. From what I've found, if you cover everything, so you can't see the layer just under them, you've put on too much. When they say light coatings, they really do mean light, but it ends up being faster and looking better than coating them entirely in 1 go.
Sorry that's probably more than you wanted, I've just been dealing with exactly this issue over the past couple days. I've only got one more rim to do, been tackling 1 a day, so I should be finished tomorrow!
Here's a pic of the first rim that I almost screwed up. It's not perfect because I had to peel back some of the spray that was too thick and cracking, but after the cans were warmed, it was easy to fix them to a point I was happy with. You can still see the minor imperfections from the issues.