Wondering, Steve, Do you notice a change in your altimeter when you open your doors in flight?
Yes, for about 1 second then it remains stable.

We've only done about 30 Kitfox like this in the last 20 years from model 3 up. My model 4 was very accurate with this set up. Never had dirt, bugs, frost, ice or other contaminates ever plug the one behind the panel.