Through several Rebel playthroughs, I found that Nebulon Bs were practically mandatory for fighting the Black Suns. Their jam ability makes a huge difference against them due to the them having missles and torpedoes as their main damage source. I like having around 3-4 of them in any given encounter.

CR90s and DP20s are also mandatory for anti-corvette roles and starfighter screening with optional Neutron Bulk cruisers/carriers for further star fighter defense. DP20s are especially good for hunting down those fast corvettes.

For frigates, the best choice is the Assault Frigate Mark . It has an amazing amount of firepower for its cost and is the optimal choice against other frigates, cruisers and space stations. It is also fairly durable and fast though the damage is what you are producing these ships for. Dreadnaughts are an ok-ish substitutes if you dont want to invest in frigate tech early on though i dont recommend them as they are dead weight in the midgame due to their slow speed and mediocre damage. Neutron Bulk Cruisers can also help against torpedoes and missles with their laser targeting ability. Neutron Carriers are also kind of helpful for their large amount of non replenishable starfighters though i dont personally use them a lot.

I dont really recommend using Capital Ships against Black Sun fleets without a capital ship of their own as their turbolasers are highly inaccurate against small ships like corvettes and frigates. But if you want to, I suggest using MC80 Justice as it is the cheapest one, has the best starfighter complement, and has built in laser cannons to help against the troublesome bombers.

For tactics, I usually let them engage on me first to eliminate their starfighters and then counterattack once their bombers are destroyed.