The other difference that you have missed is that mine cost around a third as much to build. So given any roughly equal forces I would have three times as many. You are quite right about the relative range and chance to hit though. The other thing is that there is actually three designs. One for point defense, one that is nothing but sensors. I built them to fly in groups of six. Four standard, one point defense and one sensor.
Here is the sensor variant for you.
Samhradh-E GB 20 class Gunboat 1000 tons 74 Crew 260 BP TCS 20 TH 168 EM 300
8400 km/s Armour 1 Shields 10-300 Sensors 1/0/0/0/0 Damage Control 0-0 PPV 0
Replacement Parts 1
GB MP Drive E55 (1) Power 168 Efficiency 5.50 Signature 168 Armour 0 Exp 21%
Fuel Capacity 20,000 Litres Range 15.7 billion km (21 days at full power)
Delta R300/12.5 Shields (4) Total Fuel Cost 50 Litres per day
Fire Control S03 48-6400 gb (1) Max Range: 96,000 km TS: 6400 km/s 90 79 69 58 48 38 27 17 6 0
Active Sensor MR6300-R15 gb-l (1) GPS 630 Range 6.3m km Resolution 15
Active Sensor MR40-R0.4 pd-s (1) GPS 4 Range 40k km Resolution 0.4
This guy would spot you at a much greater range. The biggest problem mine would have is you speed. You will be able to close through their longer range and get in close where you shots will be doing significantly more damage.
Here is the up to date tech GB that they would have to build to fight yours.
(They were building the others to sell to their ally. They had not updated their own because they didn't have any hostile races nearby and I was playing them as a typical semi-corrupt business empire)
Ard GB 20 class Cruiser 1000 tons 99 Crew 356 BP TCS 20 TH 250 EM 90
12500 km/s Armour 1 Shields 3-300 Sensors 1/0/0/0/0 Damage Control 0-0 PPV 4
Replacement Parts 1
GB IC Fusion Drive E75 (1) Power 250 Efficiency 7.50 Signature 250 Armour 0 Exp 60%
Fuel Capacity 20,000 Litres Range 11.5 billion km (10 days at full power)
Epsilon R300/15 Shields (1) Total Fuel Cost 15 Litres per day
R10/C4 Meson Cannon (1) Range 96,000km TS: 12500 km/s Power 4-4 RM 10 ROF 5 1 1 1 1 1 1 1 1 1 0
Fire Control S03 48-15000 gb+ (1) Max Range: 96,000 km TS: 15000 km/s 90 79 69 58 48 38 27 17 6 0
Magnetic Confinement Fusion Reactor Technology PB-1.1 AR-0 (1) Total Power Output 6 Armour 0 Exp 10%
Active Sensor MR40-R0.4 pd-s (1) GPS 4 Range 40k km Resolution 0.4
Active Sensor MR1500-R15 gb-s (1) GPS 150 Range 1.5m km Resolution 15
And here is the point defense type. The radar type has the same capabilities as before.
Ard-p GB 20 class Cruiser 1000 tons 94 Crew 350 BP TCS 20 TH 250 EM 90
12500 km/s Armour 1 Shields 3-300 Sensors 1/0/0/0/0 Damage Control 0-0 PPV 4
Replacement Parts 1
GB IC Fusion Drive E75 (1) Power 250 Efficiency 7.50 Signature 250 Armour 0 Exp 60%
Fuel Capacity 20,000 Litres Range 11.5 billion km (10 days at full power)
Epsilon R300/15 Shields (1) Total Fuel Cost 15 Litres per day
Single R7.5/C3 Meson Cannon Turret (1x1) Range 48,000km TS: 20000 km/s Power 3-3 RM 7.5 ROF 5 1 1 1 1 0 0 0 0 0 0
Fire Control S02 24-20000 pd- (1) Max Range: 48,000 km TS: 20000 km/s 79 58 38 17 0 0 0 0 0 0
Magnetic Confinement Fusion Reactor Technology PB-1.1 AR-0 (1) Total Power Output 6 Armour 0 Exp 10%
Active Sensor MR1500-R15 gb-s (1) GPS 150 Range 1.5m km Resolution 15
Active Sensor MR40-R0.4 pd-s (1) GPS 4 Range 40k km Resolution 0.4
ECCM-2C (1)