Good luck with your new project. By the way, is the person you are now working with is Jay2Jay? He said he was a coder and searching for stuff to work with. Speaking of Protonians, can you "archive" your old sprites on the spiral arms thread? This way they won't be lost forever, which would pains me.
For your new sprites, i'll mainly warn you about three things.
1: Watch out for the saturation, your old Protonian ships were over-saturated and this new one isn't an exception.
2: As people said before, you'll need to be careful about the number of weapons mounts on your ship. While weapons mounts are an easy way to "fill" the sprite, balancing the ship will become exponentially harder. For this one i can see 10 frontal medium turrets, one large and 17 small, plus the launch bay (that i tend to consider, balance wise, as an additional large weapon). The closest vanilla ship to this one would be the Odyssey but yours seems to have nearly twice as many guns.
Here's an invaluable tutorial by Psiyon to learn how to paint on sprites. I won't ask you to make entire ships from scratch but this method is extremely good if you want to "hide" some details or weapons mounts if you have too many. (works for you too, Valk!)
https://www.youtube.com/watch?v=8Wr3O4yPxZg3: Weapons mounts proximity can be an issue to look out for. In this one it feel like two of the medium mounts are too close to each other and as a result the weapons will overlap, which will looks weird.
Also not a fan of the two Aurora "fins", the ship would looks much better without those i think.