I'm not sure if there will be a prerelease tonight, but the new "Heavy Beam Cannon" line is shaping up fairly well. I added an alternate beam mechanic for it to use, such that the beam starts off really really strong but loses power as it does damage (currently on a 1:1 ratio). This allows me to pump the actual attack power back up to where I'd like it to be. With the previous straight-up line-shaped aoe attack I had to keep it so low for balance that a mk I beam cannon only did 2x the damage of a mk III laser turret, which didn't fit in my mind since there's a 4:170 ratio of how much you can build. Now it will vaporize a few bomber Is but not an arbitrary number that happened to be behind them.
FYI, my main balancing factor for dps-focused units like these is maintaining roughly the same "DPC-at-cap-per-K", that is:
Damage-per-cycle = attack-power / cycles-to-recharge (20 cycles per second)
cap = ship cap (170 for laser turrets, 4 for beam cannons)
K = knowledge cost for that tier
( (attack-power / cycles-to-recharge) * cap) / knowledge-cost
Currently the beam cannon's DPC-Cap-K is slightly better at each tier than the laser turrets, to make up for the fact that 170 ships will have a much more flexible and probably efficient application of their total damage.
Metal, Crystal, and Energy costs are also balanced to be in the same ballpark, each shifted a bit to fit with the concept behind the unit (high energy, or high metal, etc).