Since you're learning how to play shieldfac, which is a good easy fac, just learn about how to make a shieldball.
Try replacing some or all of your Rogues with Thugs. Add a couple Outlaws if the enemy is using raiders, or just a Felon once you've built enough shield power (4-6 thugs). Once you have a couple Felons, add in Aegis. A felon shieldball will butcher most Gunship compositions.
You might also want to try just adding Racketeers. They counter both Tanks and Stingers, and even the heavier gunships (Blackdawn/Brawler). They'll work quite well alongside your current Rogue/Bandit composition (Though you should learn how to make shieldballs too).
If you own most of the map and are worried about trasitioning out of bandits and not being able to respond to enemy raids, static defenses of your own are not a bad option, particularly Lotuses which are very strong against raiders. These won't be as much use against his Tank/Gunship switch though.
If the gunship switch is the real problem, just make sure you have AA prepared, make a Razors Kiss or two at about 8-10 minutes (Or whenever you expect the switch). Consider going Planes, even if you just use the fighters, they generally counter gunships unless he is spamming Rapier (In which case, I'd suggest just eat them with a felon ball).
