Balance suggestions for new ShipSize

[Suicide Junkie]

For Pirates & Nomads v2, I was planning on adding a new shipsize.

It would require max tech in ship con. and base con., and probably a little SM.

A BattleMoon, ~10,000kT size, with 50x damage CoreMount available. (so a CM meson bLaster does 1500 damage at long range) 20 engines will provide one movement point (max), and the picture of the ship will be the same as a tiny moon. I expect the price to be over $1,000,000 for construction, and it will have a 25% reduction in maintenance (its part-planet, part-base, part-ship)
(Think ShadowRaiders for those who saw the show )
One of these should be able to take on 20 or so LCs, based on my rough calculations.

Note: I will have (weak) armor components that block null-space and other armor skipping weapons, so it won't be totally vulnerable to NSPs.

What I need are suggestions on how to keep it balanced, and people to point out problems I've missed.