[@WilsonTurner]Well, this is kinda new to see somebody who's actually aware of this.
Yes, your ship is effectively a superweapon of sorts.
Although if can only fire in every 3 hours its point cost would drop severely.
There's also that while I can see it mission killing medium sized ships, bigger and more durable vessels may survive the attack with only moderate damage.
DEWs aren't particularly the best when dealing large-scale destruction.
Once they penetrate the hull, the rest of their energy is wasted.
Unless you have some kind of idea to deal with this issue, of course. (I have several options in mind)

Anyways, I don't plan a "pre-fight phase" in battles. Neither I think ou need them.
Just think of these ships as "nukes" which if you use well they can be devastating during the battle.
Also "realistically" I think 3 hours maybe even a bit excessive for cooling the guns. How about them exchanging "barrels" instead?
The carrier of the Lightships would would carry spares while busy cooling the used ones.
This may allow you to do more than one shot during battle.
Of course the said carrier would also cost points but it won't be horrendous in that aspect.
You don't need to worry about keeping the carrier on the "battlefield", either. I just need to be a bit more flexible when describing the combat zone, including some details even outside of it.
On the other hand I won't allow players to launch hyperspace-capable torpedoes and such from outside the combat zone. That'd be too cheap.