CONGRATS ON YOUR NEW 22WSM!! I've only cooked on one once (thanks,
@WNC !!) and it was a dream.
I know a lot of folks rave about the CB doors, but I just don't see the need. Perhaps because I don't do cold smoking or other more challenging cooks-- I just use my smoker for 225-275 smoking, with the occassional snake-fueled 180 cook for smoking peppers.
In my experience, the most important part of getting a tight seal is having a good layer of seasoning in your cooker. In my case, I bought a used 18WSM that had plenty of cooks on it (my mouth was watering the whole way home from the CL pickup), but it was still hard for me to control temps-- they would rise up to 300 if I didn't keep a close eye on things. But after many more months of smoking, my cooker gunked up and cooled down and it's been a dream to cook on ever since.
Too, under the influence of Aaron Franklin, I've changed up my way of smoking. Instead of loading the WSM up with tons of charcoal and then choking it down for a very long cook, I'm now using much smaller fires with a lot more airflow. And again in my experience the product is tastier than it has ever been. When I do overnight cooks I kind of split the difference between small and large fires, but I still have no need for a very tight seal in my smoker-- quite the contrary, in fact.