Welcome oldeboone, I had an electric brinkman, the problem with adding vents is that IMHO the heating element will just run more to try to get to the temp. you have set on the controller. I would try to turn down the controller below your lowest setting it is a reastat and should work even if turned below the low setting. As for the bar oil question I know a guy that has two saws. When he knows he is cutting wood for smoking he has a saw he uses cooking oil instead of bar oil.
I was going to ask about bar oil but I ran a search first, and found this thread.
I recently got some windfall maple, and someone had cut it with a chain saw that left a lot of blue oil on the cut ends. I cut those stained ends off with a bow saw.
I have a little 8-inch chain saw that I sometimes use for cutting wood for the smoker, but it never leaves visible oil. I was wondering if the general wisdom of the board tolerates any oil contamination at all.
If a chain saw is leaving visible oil on the cut wood it needs to be serviced. A properly operating saw with an automatic oiling system will not leave oil on the cut wood. Using bar and chain oil is not an issue if the saw is running properly.
I would never use any oil other than that recommended by the manufacturer, especially not cooking oil.