So I'm running a double cymoon list with 2 flotillas and no squads. Should I trade the flotillas for a small fighter ball about 70 pts?

Just won a store champs with a similar double cymoon list bringing Cienna and Valen. They will slow down a bomber ball for enough turns to have your cymoons kill the enemy carriers, and they're only 30 points. If you have a bit more to spend, Maarek and Jendon will allow one of your flotillas to pump out a pretty consistent 4 damage a turn if your opponent goes squadronless. I've killed many a Corvette that thought it was safe after getting out of my front arcs with those two. Jendons relay helps send Maarek pretty far way from the commanding goz too.

I'd say swap a flotilla for Strategic Advisor and take a few anti-fighter squads at least.

Here's the list...

Name: WTF without Squads copy
Faction: Imperial
Commander: Darth Vader

Assault: Station Assault
Defense: Contested Outpost
Navigation: Dangerous Territory

ISD Cymoon 1 Refit (112)
• Wulff Yularen (7)
• Intensify Firepower! (6)
• Gunnery Team (7)
• Quad Turbolaser Cannons (10)
• H9 Turbolasers (8)
= 150 Points

ISD Cymoon 1 Refit (112)
• Darth Vader (36)
• Strategic Adviser (4)
• Gunnery Team (7)
• Quad Turbolaser Cannons (10)
• H9 Turbolasers (8)
= 177 Points

You could run two comms net flottilas with that (50 pts) and C/V (30 pts) and come out at 397. How important is a bid for you? I recommend at least one flotilla because that opens up Most Wanted to be your red objective if you're going second (yay more cymoon dice!)