Every combination is different and every fuel will have different requirements. For a guy who runs in really good air like you do I would say most your DA swings are due to temp and grains/VP. I would say for "normal" race fuel 6-800' would be where I would look to change something. Out here we can have huge DA swings from track to track due mainly to elevations. And that is an entirely different animal we will see ACTUAL barometer readings anywhere form 29.8-9 to as low as 25.6. Trusty me 27.6 baro (Vegas number)DA can be the same as 29.8 baro DA but you will need a completely different tune up to run. A lot more to the DA than a simple number but for you east coast guys the barometer is always good from what I've seen