Averyminya
Grasshopper Backer
I roll the temp dial all the way down and all the way up so I can estimate where the middle is and go from there. That won't work for the precision you're after though.
I've also been here. It can be a little scary in public, because you might take a dank rip on accident if you go too high (say you took a hit on 1.4 and then go up to 3.2... 3.2 is gonna smeeeeell!). When I used it in a theater I used bright scenes to get the temperature I wanted. Otherwise, cell phone lights are what I've used. It's a little troublesome at times, but never that big an issue.