I like to cold smoking my belly bacon, so the fat does not render out, but I've also taken the internal up to 120*. Both ways produced great bacon, but a little better color with heat. Smoke for 6 1/2 hours is just right for me, but some guys like a little more smoke.
Try running the internal temp up and see if you like it. I set my heat to 150* in my MES.
Todd is right,
With Belly Bacon, I don't like to go over 160˚ smoking temp, and that would only be near the end to get it nice & brown, if it wasn't already.
My favorite way, once you have a pellicle formed, is to go gradually up from 100˚ to 160˚, maybe stopping for an hour every 10˚.
However, if you really want to cold smoke, you shouldn't go over 100˚.
I have removed my Belly Bacons at anywhere from 100˚ to 142˚. They were all Great, but I had the best color on the ones with the higher temps.
It is my opinion that you need a little heat to add to the smoke to get the nicest color, but I still would not take the smoker above 160˚ with a Belly.
These temps are only in a smoker that can be controlled real well. My MES 30 & MES 40 can do it real good, however it is hard to get consistent smoke with them at those temps. An addition of a cold smoke generator fixes that problem. Most people, including me recommend the "A-MAZE-N-SMOKER". That things solves All smoking problems.