Not seeing reversion on the baseplate. IFR location is probably not a major player in this case. I see no harm in lowering it though.
Well go back and read what I wrote 'cause I hate typing if your not reading.
16 at what? 16 at 1000 is probably something else at 900 or 700.
Halfway on a large sight glass is usually the nromal starting point. Bottom of the small sight glass on most older bowls.
Running or engine off the fuel level should be about the same. If not there's a leak.