How well do the missiles do against an opponent of the same tech level and tonnage?
That would very much depend on the design of the ships of the two races. In this case, the attackers are lower tech, but have a 5-1 tonnage advantage. However, a third of that tonnage is AMM escorts and energy escorts, which are not directly involved, and the ships launching missiles are hybrid energy/missile combatants (see example below), so only a portion of their tonnage is effective. Conversely, the bases they are attacking are designed purely for anti-missile defence.
Royal Sovereign class Battleship 28,125 tons 764 Crew 4,135.8 BP TCS 562 TH 1,800 EM 0
3200 km/s Armour 8-82 Shields 0-0 HTK 163 Sensors 6/24/0/0 DCR 20-7 PPV 156.8
Maint Life 2.22 Years MSP 1,838 AFR 316% IFR 4.4% 1YR 504 5YR 7,564 Max Repair 300 MSP
Magazine 963 / 0
Commander Control Rating 2 BRG AUX
Intended Deployment Time: 12 months Morale Check Required
Parsons PN-600 Triple Expansion Gas-Core Drive (3) Power 1800 Fuel Use 28.58% Signature 600 Explosion 10%
Fuel Capacity 817,000 Litres Range 18.3 billion km (66 days at full power)
Twin 8-inch Ultraviolet Laser Turret (4x2) Range 256,000km TS: 8000 km/s Power 20-7 RM 40,000 km ROF 15
Twin 5-inch QF Ultraviolet Laser Turret (4x2) Range 160,000km TS: 8000 km/s Power 8-8 RM 40,000 km ROF 5
4-inch QF Railgun (8x4) Range 20,000km TS: 4,000 km/s Power 3-3 RM 20,000 km ROF 5
Barr and Stroud MK I Primary Laser Fire Control (2) Max Range: 256,000 km TS: 8,000 km/s ECCM-1 96 92 88 84 80 77 73 69 65 61
Barr and Stroud MK I Railgun Fire Control (2) Max Range: 80,000 km TS: 4,000 km/s ECCM-1 88 75 62 50 38 25 12 0 0 0
R-21 Gaseous Fission Reactor (4) Total Power Output 85.2 Exp 5%
Armstrong Whitworth AW-12 Missile Launcher (8) Missile Size: 12 Rate of Fire 695
Maxwell MF-60 Missile Fire Control (2) Range 63m km Resolution 120 ECCM-1
Perseus Anti-Ship Missile (80) Speed: 22,500 km/s End: 29.7m Range: 40.1m km WH: 9 Size: 12 TH: 75/45/22
Maxwell MX-6M Missile Detection Sensor (1) GPS 16 Range 6.4m km MCR 574.5k km Resolution 1
Maxwell MX-80 Active Search Sensor (1) GPS 13440 Range 83.3m km Resolution 120
Rutherford RT-6 Thermal Sensor (1) Sensitivity 6 Detect Sig Strength 1000: 19.4m km
Rutherford RE-24 EM Sensor (1) Sensitivity 24 Detect Sig Strength 1000: 38.7m km