Space stations are underpowered in the SE series. The lack of need for movement should allow a much size greater advantage.
How about calling the basic station an 'Outpost'? After all, they start at 600 kt, which is merely the size of a cruiser. Add a few levels so it can reach 1500 kt. Then you can have a true 'space station' start at 2000 kt or so. And then bump starbases up to something more. At least 3500 kt. They should max-out at 5000-6000 kt or so.
For ship sizes, we don't need anything smaller. We need a class between dreadnought and baseship, though. Maybe borrow 'Titan' class from Moo? Or even Behemoth and Leviathan from Moo3.
Baseship should still be the largest, and still use the starbase model. And it should be limited to a movement rate of ONE in all circumstances. It's just too huge to move faster without miraculous 'Q' powers.