We closed everything up and he installed a fan blowing out the front door. That put a vacuum on the house and sucked cold air in from all of the little holes and cracks that we didn't have plugged. After a couple of minutes, we walked around with his thermal camera and could see the cold spots. There weren't many, but it was good to note them so that we filled them before installing the ceiling and drywall.
The results were 0.9 ACH50. This means at 50 pascals of vacuum, we have almost one complete air change of the house per hour. A typical house is 5-10! Our's will most likely drop some more also when the drywall is in and cracks are filled. Some pics below. That's me in the left and our radiant heat in the right (looking up at the basment ceiling).
Makr and his stuff