I haven't even modified them yet, my skills are quite poor. In any regards I had a funny bug where I couldn't see 3 of the upgrade slots as they were hidden behind the ship, it is not even more impressive! Please post an update!
Right now if you have a crewed ship in a different system it is not active, however, the crew pay keeps ticking. A mod where you could activate / deactivate crew pay in total or per ship. Either through freezing the timer or reducing the cost?