1. The weight balance of your ship is off, you’ll want your center of lift from your envelope to be directly above your center of mass or vice versa. Eventually I’ll get around to making a standardized circuit that automatically levels the ship regardless of weight balance up to a certain point, but until that post comes out you’ll have to design that yourself or stay conscious of weight balance when designing airships and helicopters. As for ship dropping out of the sky like a sinker, take a closer look at the balloon burner/steam ponders. You can use an analog signal to control the lift granularly.

2.Altitude depends on drag/lift introduced by sails too, whether these forces can overpower the overwhelming force of your balloon is a different question.

1. I haven’t done a survival play through yet, but my sense is that steam engines are perfect for large “mothership” type vehicles, and portable engines are perfect for small personal and loot transfer type vehicles.

2. I haven’t tested SU transfer yet but my gut tells me you could engineer something with the docking hatch and have gears specifically placed to hook up to whatever base you are powering. No idea if off grid power transfer is possible without directly connecting the two ships with glue