I haven't even found that much reason to use counterspell or even have Gale use Shield at all because there were so few spellcasters with actual threatening spells or anyone actually targeting Gale.
not sure what you did differently (are you sure it was tactician?), but for me the enemies targeted gale *fanatically*. as long as he was detected, they would forget anything else and try to kill him. i ended up having him sit out most fights outside of combat, occasionally re-summoning connor, casting distraction cantrips, and sometimes concentrating on something.
I usually kept Gale way far back, but I also built him in a way that he ended up with 18 AC after using Mage Armor but before using Shield. The AI likely figured that the rest of my party were far more attractive targets. Especially Karlach who has the lowest AC in my party, and Shadowheart who is usually concentrating on Spirit Guardians. Meanwhile my Gale is rarely concentrating on anything or he's throwing Haste on my Bard and then hiding even further back. (My archery build College of Swords Bard is rocking 22 AC and enemies seem to like targeting him over Gale when they actually do get close enough to threaten them both, but that's probably because an archery build Swords Bard does absolutely bonkers damage to the point where he's usually one-rounding one or two enemies every single turn along with the fact that he actually has slightly lower max HP than Gale, and I think that influences enemy targeting somewhat.)
