I'm using the Clear Star LL semi-gloss and dilute it with 20% distilled water.
If I have enough large canvas prints, I'll put it through the Daige EZ Glide. Otherwise, I'll foam-roll it on my hand.
For smaller runs, I'll hand roll the liquid laminate. You'll got to put it on generously and keep the roller going until you get an even sheen. You'll really need to soak in the coating to keep it even. With hand rolling, you'll have a good chance of picking up some debris unless you are very meticulous with your work area.
For the Daige, I've found the best results by coating and drying and then coating a second time. The surface after the second coating is just about perfect!
In ether case, I've coated from about 10-30+ degrees (about 50-85+). It seems to work fine, but I prefer warmer in the winter and cooler in the summer!
No matter how you coat, give yourself an inch or more margin on the prints for drips, handling, slop, etc.