as you requested so you shall receive here is the analysis of all the ships I had compared including actual damage values and a modified value which shows damage and health by population point cost so that ships with varying population points can be compared. I have not done every ship, I mostly focused on Imperial and EoTH, but I read somewhere that the nebula was supposed to be really strong so I included it too.
ship class hull/shield daamage population health and shields damage/population hull and shields / population
acendancy 780/910 pop 3 5330/5330 hp/shields 260/303 1776/1776
phalenx 1620 pop 5 8000/8000 hp/shields 324 1600/1600
syndic 575/887 pop 4 6210/6210 hp/shields 143/221 1552/1552
budirch 400 pop 3 2500/2500 hp/shields 133 833/833
chaff 364.8/924.8 pop 3 3900/3900 hp/shields 121/308 1300/1300
praetor 1020/1860 pop 9 11700/11700 hp/shields 113/206 1300/1300
isd I 430/1030 pop 4 5000/5000 hp/shields 107/257 1250/1250
isd II 679/939 pop 4 5000/5200 hp/shields 169/234 1250/1300
vsd I 945 pop 3 3185/3185 hp/shields 315 1061/1061
vsd II 460/660 pop 3 3185/3185 hp/shields 153/220 1061/1061
tector 858/1482 pop 4 8030/8030 hp/shields 214/370 2007/2007
katana drd 350/550 pop 2 2310/2310 175/275 1155/1155
ssd 6530/8530 pop 15 40310/40310 hp/shields 435/568 2687/2687
ccvsd 560/960 pop 3 3185/3185 hp/shields 186/320 1061/1061
nebula 634/834 pop 5 5110/5110 hp/shields 126/166 1022/1022
viscount 6690/8690 pop 18 40310/45310 hp/shields 371/482 2239/2517
I wont swear the table is 100% accurate, I caught a couple of mistakes I had made but there might be more, all the same, it should be accurate for the data I used.
As you requested you can see the data for the crimson VSDII VSDI and the ISDI and ISD2, to compare I will put a single one against a structure with n hard points, 5000 health and 5000 shields, since I am not sure if the shield refresh rate occurs on a per second interval I will for now ignore shield regeneration. I will also avoid using power to weapons as I am unsure of the exact multiplier and also the duration. the unitized columns are the values as calculated for a one population point ship with the same damage efficiency as the ship in the row, this is done to ease the comparison since ships costing three and four population points are being compared in it.
ship seconds before hitting hull total destruction time unitized seconds before hull unitized destruction time
ISD I 19.41 seconds 64.32 seconds 77.64 seconds 257.28 seconds
ISD II 21.30 seconds 48.05 seconds 85.2 seconds 192.2 seconds
VSD I 21.16 seconds 42.33 seconds 63.48 seconds 126.99 seconds
crimson VSD II 20.83 seconds 53.38 seconds 62.49 seconds 160.14 seconds
just in case it is unclear, the lower number is better in every column.
Now, if we just compare the first and third columns, there is not as big a disparity and since as was pointed out, in most cases a single volley will destroy a hard point, the times in the second and fourth columns might not matter as much, though it will help you decide what ships to drop in against the large shipyard you are trying to blow up with your hit and fade.
can ships switch targets mid salvo? I thought they could, since to speed up the destruction of capital ships and stations I would have my ship switch targets before a hard point was destroyed so that the projectiles still in the air would kill the hard point while I fired at a different one.
Based on this analysis, ignoring super ships which are very very efficient (excluding the praetor anyway) the most efficient ships I tested are the Tector, the Ascendancy, and the Phalanx class ships since they have a combination of high health and damage per population point. The VSDI is also a very efficient ship damage wise, but its health is lackluster. This analysis does not take into account star fighter complement, which I believe makes the Tector go down a lot and most of the other efficient ships go down at least a little, but depending on whether we are going by total squadron count or max simultaneous deploys, the Ascendancy might actually go up in efficiency since it can have 4 squadrons deployed at once, though that is also the number it can carry.