Monokote shriks well at about 300 degrees and up. Just watch that you don't get it above about 375 as you can melt a hole in it as it nears 400. A good heat gun is the way to shrink. For me, an iron is harder to get a nice flat shrink. I use the iron to tack the covering down all the way around, as tight as I can, then heat gun the rest. To really shrink tight, I reduce the intake area of my heat gun by about 25%. I just place a finger across one of the 4 holes in the back. It's important to keep the iron moving to avoid melting. Start about 3 inches away, the get closer if you must. KEEP THE GUN MOVING.