If you are going to have limited use rocket boosters, which is a good thing, then no ship should have more than three uses of it. Probably only one or two ships should get 3 uses, most would have 0-2. Rocket boosters are a lot of fun and can be used in a lot of ways. They also give the slower ships a limited ability to catch faster ships at just the right moment. Their are two primary things that they are used for. Defensively, and what they get used for most often, is as a “save me” button. You hit the boosters and just get out of whatever situation that you are in.
Offensively, as someone else hear already noticed with Trandals, the momentum of the ship is imparted to the projectile. Shots travel faster and farther, and faster means more accurate, when fired while on rocket boosters. As you can see on Trandals, this is hard to do while holding down Trandals speed boost button. So if you add “consumable” rocket boosters”, make them function like “rocket boosters”. You don't have to hold the button down, activating the rocket boosters “ignites” them and there is no turning them off. This frees your finger fire the fire button if you are using them offensively. I call offensive use of rocket boosts like this the “needle injection attack” because that's what it felt like with Subspace's “little dot bullet guns”.
Only a few of the current weapons will have any type of “needle injection attack” capability, so rocket boosters will change the weapon balance enhancing those ships weapons and not others. For example the Scryve and Dan'nath don't gain a new form of offensive attack with this (and Scrvye probably shouldn't even have rocket boosters).
Rocket boosters will also provide another means of you seeing that things are generally still moving a little too fast, but only a little now. Rocket boosters should have a brief acceleration too them, to make them feel right, and then boost you about 6 inches or so across the screen. The ships are still moving too fast to make this “brief acceleration” feel right. You are trying to achieve a “smooth and flowing” motion that creates the “Pattern Recognition Addiction” that made a lot of the early arcades games so addicting. Right now I think you are in a place where most of the ships are currently moving about the speed that the very fastest few ships should be moving.
I'll do another big post about ships after I play it this weekend, but the Scryve Scout should be flying more like the Tywom. I think what you are wanting to achieve with the Tywom based on how you have it now is actually “high thrust/second tier speed”. Right now you have it as the fastest ship, and it has so little thrust it is still like the “too fast” ships of the last version. I'm pretty sure what you are wanting is not for it to be the fastest ship, the Scryve Scout should be, but for the Tywom to be the most maneuverable ship. Too high a speed actually works against the Tywom ship, it makes it a lot harder to use it's gun.