I've already designed and built one of these:
ADC Leucotis class Decoy 1,000 tons 4 Crew 192.8 BP TCS 20 TH 360 EM 0
18000 km/s Armour 1-8 Shields 0-0 Sensors 1/1/0/0 Damage Control Rating 0 PPV 0
Maint Life 1.37 Years MSP 12 AFR 80% IFR 1.1% 1YR 7 5YR 103 Max Repair 10 MSP
Intended Deployment Time: 0.1 months Spare Berths 6
20 EP Magneto-plasma Drive (18) Power 20 Fuel Use 69.18% Signature 20 Exp 12%
Fuel Capacity 5,000 Litres Range 1.3 billion km (20 hours at full power)
I've also SM'ed my fighters to have just one 25% size reduction missile launcher instead of the box launchers. They can reload those. So, they're useful again, even if they only have 1 launcher instead of 2.
EDIT:
An additional factor is that my line ships are now MUCH better designs. This war has taught me a number of lessons, and I have compensated for those with refits of my entire fleet (although the carrier won't get the upgrade before I go back in).
My Diadem cruisers should be able to eliminate the threat completely from 150 million km away (well outside their range). They have enough missiles for 70+ salvos of 10 missiles each. If they run out of missiles, I have a collier to reload them periodically. It carries a complete reload for 1 cruiser. I'll also have the missiles on the carrier, and all the bombers (which can now fire again).
This should, ideally, be enough to take out all of their launchers.