The science of cooking under low temperatures - some questions.

bboulier

Today I cooked chicken parts on a KJ Classic (equivalent to a Large
BGE).  The temperature was 13 degrees Fahrenheit with 40 to 50 mile an
hour winds.   Lest there be any offense, what I want to do is to compare
this cook with others I have done on medium BGE.  First, a description
of the cook and then some scientific speculations.  Pictures are
attached.

The chicken was cut into parts and cooked at around 300
- 350 on the KJ Classic for about 1 hour.  (Speculations below.) 
Painted with a cooked mixture of ketchup, black pepper, honey, dried
mustard, Worcesetershire sauce, apple vinegar, onion powder, and
garlic  Cooked for an additional 15 minutes and brought inside.  

Scientific questions:

1. 
The KJ classic took a long time to heat up to a temp of 350, much
longer than the medium BGE would have done. Is this delay is because the
KJ classic has higher mass than the medium BGE?

2.  During the
cook, the temp at the grill was not above 300, but it cooked more like
350 in terms of when the food was finished.  Scientific question:  Is
there a greater difference between the dome temperature and the grill
temperature when the outside temperature is very low?  I believe this is
true, but would welcome other comments.