I dont agree, heres my thoughts on it.
80, 125 ton Railgun fighters that use a 1 shot railgun are 10,000 tons
20, 500 ton Railgun fighters that use a 4 shot railgun are 10,000 tons (Keep in mind atm 400-500 tons is the amount required for railgun fighters due to BFC size, railgun weapon size and reactor size)
Both fire the exact same number of shots so in terms of PD they are the same, for anti ship railguns themselves have one of the worst damage patterns anyway so if its in chunks of four or 1 it will do around the same.
Now in terms of fuel efficiency yes larger fighters will be better but this is offset by the fact that you dont make beam fighters for their fuel efficiency you make them for their very fast speed and flexibility.
I agree with the point that 80+ Fighters are gonna be insanely hard to deal with for some fleets and you may overwhelm the enemy as they may have the weapons to destroy them or the ammo but they cant target enough of the fighters at a time before they themselves take damage, not only will this provide a useful distraction its also very dangerous especially when you combine this with other weapons as the enemy PD, missile and other capabilities will be fired a these fighters which are small, hard to hit due to speed and expendable.
A 500t fighter in a pure engagement will almost always win given equal tech level... they can have more armour use more efficient engines and require less space for fire-controls and sensors. They are just way more durable than the small ones. The only benefit of being small is essentially the stealth factor in terms of fighters so they are harder to fight with missiles. But as long as the opponent know your fighters size even this matters very little in the end.
A heavier fighter also can fit a heavier beam weapons which is deadly to other fighters even with less DPS.
I disagree on some of the points.
1A - Armour is not important for fighters really due to various reasons, 1. they cant even fit more armour on space wise because of how tight the margins are for beamfighters, 2. Most things that will hit it will do enough damage/shock damage to disable the fighter if not destroy it, 3. Fighters are generally expendable so putting armour on is just extra cost for not much gain.
2A - In terms of BFCs the main tonnage sink is the engines and the weapon for example on one of my railgun fighters 350 of the 500 tons are already gone for the weapon and engine, BFCs atm tend to be around 50 tons, reactors 30-35 at around Ion-magneto, and the rest is fuel, so while your correct you have less space in practise not really at all, since percent wise its gonna be the same with the changes made, also the idea of "sensors" on a beamfighter is just dumb, any beamfighter will not have its own sensors as its too much tonnage that could be used on fuel or anything else as beamfighters are inherently quite massive, instead they use their carries or an AWACs that accompanies them.
3A - I disagree that the only benefit is stealth yes that is one of the benefits but as stated in the previous post if you have 80 fighters instead of 20 you have 60 more targets for the enemy to shoot at, and lets be real if you get hit once in a fighter theres an 80% chance its either disabled or destroyed so this will actually massively increase survivability in terms of endurance in being effective.
4A - While technically this is true it doesnt change tonnage efficiency or anything else, now for lasers fighters you may have a point as a larger laser can and will penetrate deeper but for railgun fighters this matters little as railgun damage pattern is not good at all.
At the end of the day we can argue forever but I for one am happy we have more choice in 1.13 where we can decide on what doctrine to use fighter wise either swarm or heavier more deadly fighters, we dont have this in 1.12, keep in mind this is all preference, peoples own doctrine and how they use fighters so its gonna be heavily subjective in many regards.
