Very nice sprites for a first time but the balance is a bit off.
Gemini(PL) is essentially a completely superior version of the Drover, which already is a very strong(especially with mods adding wings) ship. 3 bays and Reserve Deployment is strong by itself, even more so on a 13DP destroyer. Even if one of the bays is an inbuilt. And definitely reduce how frequently this ship appears because it feels like every persean fleet I fight is 50% Gemini(PL).
Like other folks have said, Sentinel needs some big nerfs. Reserve Deployment is already an extremly strong system, so I think it's gonna be really hard to make Reserve Fleet not a "delete target ship" button, especially on a ship that already has 8 bays. I think you'd need to at least drop it to 6 bays(keeping 2 of them with inbuilt wings) if you want it to be balanced. Fighter spam is not very fun to fight unfortunately.
Can't say much more as I haven't played enough, but the fighters do feel a little on the strong side, though any judgement of that is hard with how many of them the two offenders mentioned above can output.