I smoke on the same smoker badger. A couple tips i have found that helps to hold heat.. I use a bungee to hold the lids down. Hook it on the frame then over the handle for the door, being careful not to let it touch the barrel. Anywhere you see smoke leaking from under the lid and not from the stack is a place you're also losing heat.
Use a water pan. I usually mix water, garlic, Worcestershire sauce, and a couple apple slices in mine. But even if it's just water that's fine.. I like to put one in there to raise the humidity as it helps raise the heat, keep things moist, and helps the smoke penetrate the meat.
The damper over the stack on mine is never open more than 1/4 inch unless i'm getting the coals ready. All of my temp adjustments are done from the air intake in the firebox. On cold days like this, I may have it open 3/4 of the way to hold the temp.
Looks fuggin good man.. Hopefully some of that helps get the temps up better.