Changed my mind, it's better to have SEP_ALT relative to the sea level. Because if for a reason it reboots in flight, it'll take the actual altitude as ground altitude and never separate. While if we use sea level as a reference, whatever the reboot altitude is, it'll always deploy daughter at the right altitude.
More delay after opening and before control start to give more time for the wing to stabilize.
New feature : ground altitude, used to make sure the ground altitude is not reset after the flight has started, even if a GPS fix is lost for a few minutes before being regained
New old feature, but not tested again : cog_brake, will reduce command if turn rate is too high, but might not be really necessary with a good PID controller.. so..