As I recall the issue of summoning is easy to deal with using the dialog
interface. Just click on Deekin and tell him that you want to adjust his tactics, then
change how he uses combat spells, then tell him not to summon help.
Done.
Oh, wait! You're not using
Tony K's AI?!? Guys, this is the exact sort of thing in which the AI really shines. After playing the OC once with henchmen and no AI overrides, I pretty much gave up on the use of henchmen. I liked the idea of a party, for the most part, but it became too frustrating to micromanage the henchies When I was most of the way through another run through the OC, to "freshen up" some skills before starting HotU (having gone through almost all of SoU alone with a different character), I stumbled on Tony K's AI and figured, "Why not? If it doesn't work, I drop off Sharwyn at Aarin Gend's daycare center and continue on my way." But, with the new AI, henchmen were fun again! Not perfect, of course, but playable without being endlessly frustrating. Just install it and do as recommended above. Sooooo much better... :-)
During HotU, I had Deekin with me through most of chapters 2 and 3 and I asked him not to use spells except for pre-battle buffing I manually asked for when I thought we were about to
BTW, as an aside related to the other question, one of the first things I discovered with Sharwyn was to tell her not to summon help. I had given her a Harp of Haunting that we found, thinking that the Fear spell might keep some of the mobs from swarming us. The first thing she did was summon a tyrantfog zombie. For one thing, that's disgusting! Don't summon "help" that I think the hostiles are doing us a favor by killing off. Second, GIVE ME BACK MY XP, YOU WALKING GARLIC FERMENTATION FACTORY! :-)