Spinal lasers of really large size is brutal and can cause massive damage through sheer chock if it does not outright tear through the armour. Combination of heavy hitters and fast firing high rate of fire lasers are very effective.
In this case though... since you also have particle lances I would agree that Spinal lasers don't make that much sense other than for the fun factor... if you have them then why not use them I say.
In terms of the launcher and smaller salvo size it really does not matter... instead of arriving to the battlefield with one Cruiser and a handful of escorts you arrive with two battle cruisers with no escorts as they bring their own defences anyway that way. Now you also have the option of choosing how many offensive and defensive missiles they carry and what types and you can change them in the field from long, medium or short range missiles and in which proportion of AMM versus ASM they carry at any time. It also is very easy to use excessive force with box launchers and then leave you open for a surprise counterattack from a hidden force.
In my opinion versatility is more important... you still would have the same throw weight... it is just a measure of how much do you value defence or offence. If you bring 4 cruisers with 120 missiles you have half the defensive capacity as if you bring 8 cruisers to do the same job. If you don't care about the defence and you find that it is good enough then all is well, that is the doctrine you set out to have, there are many example in our world where both have been successfully used.
My doctrine usually go by the metric that any battle-group must be able to handle an enemy at least three times it size in terms of missile defences using a layered defence strategy. If I ever intend to assault something the minimum battle doctrine dictate at least a 5:1 strength in my favour or the assault are deemed too risky as you can't ever know all the details.
According to this logic if you arrive with 8 ships with the same missile firepower for the same(ish) cost you can arrive with 8 ships with 2x the firepower and enough PD to handle the more defensive minded fleet offensive missiles.
It's interesting to think about the possibilities. 2 defensive fleet cannot really hurt eachother with missiles 2 offensive fleet can hurt eachother pretty well. But in an offensive vs deffensive situation it's back to no real damage.
One thing to note here is that defense is much harder against missiles as offence in my opinion.
You waste allot less resources on defences against missiles if you can defend against them. It's only if the defences get overwhelmed that you don't.
I also take the option of no one doing damage over both killing each other... the problem with the latter is that it can easily be one fleet that obliterate the other because of some outside or random fluke. It is not the most sound doctrine in my opinion to rely on luck if you can avoid it.
I usually consider at least an expected 3-5:1 is realistic as that give allot of leeway for misjudgement or bad luck if I go on the offensive. If I can't bring overwhelming force I would rarely bother in the first place.
Glass canon tactic in Aurora can become very expensive... at least if you can defend you usually expend less resources than the other side did.
The other thing is versatility, being able to bring more or less AMM versus ASM or different types of ASM... those things are stuff you can't put a price on that is VERY important in practice but rarely in theory.
