But I still subscribe to the idea that McCoy had the steadiest hands in the ship...
My take too. The procedure to modify the torpedo may have required some delicate work, something surgeon McCoy would be capable of.
I dunno.... Didn't Chang point out in the trial that McCoy's hands were shaking? And didn't he admit to a touch of arthritis? Don't wait for the translation -- answer me NOW!!!!
However you spin it, the torpedo specialists would still be your go-to guys for on the fly mods.
And it still seems WAY out of character for Kirk to just sit there getting the sh!t kicked out of him without even TRYING to talk/threaten/taunt/negotiate with Chang....