I have a horse that *crosses fingers* used to like to pull the same tricks. What "fixed" her was riding her pretty hard when we were out (so she was tired going home) and switching her bit, for the time being, to a pelham with double reins.
I rode her on the snaffle rein for the most part - whenever she was behaving, but as soon as she got out of line, suddenly, magically, she had a curb bit in her mouth to slow her down (since I engaged the curb rein). Haha
The double reins were a little tricky to figure out at first but I got two pair of western reins (the "one long rein" kind) in two different widths, lengths, and colors so I could see and feel which was which. I put the longer rein on the curb part so I would never accidentally engage the curb.
The only reason I suggest a pelham is that I was able to successfully transfer my mare out of it and back down to a simple snaffle because she respects the snaffle now (after learning that it can turn into a magic curb, hahaha!).
First though , if I were you, I might get a nice french-link snaffle (or since you say he dislikes that, maybe a single joint) and ride him around in an arena, if you have one, or a fenced in field, or basically somewhere where he is contained by fences as well as by you.
Then, ride him around, get a feel for him in the snaffle, try him out at all gaits, just see if he really needs a stronger bit when he gets excited or if he's bolting due to a training issue you couldn't detect in the TT or out of a pain response to the TT. If it's just a training issue (like, he needs to get softer on the bit/etc) and not a personality trait, there will be indicators in the "arena" and you can work on those. I bet, if that's the case, you'll get those issues ironed out and take him on a trail ride and be like "what? He hasn't tried to kill me yet!!"
I don't have any experience with Kimberwicks or Bauchers. However, I'm not a huge fan of the idea of Kimberwicks since there's never a way to completely remove the curb like pressure and since I think of stronger bits, in the english world, as a way to get to a softer bit, Kimberwicks kinda defeat that purpose for me.
Bauchers, the snaffle part of my pelham is basically a Baucher and I can say that there was never any poll pressure with it. I Googled it because I too thought Bauchers=poll pressure, but apparently the majority of internet people is pretty sure that the poll pressure thing is an old wives tale. I did read that apparently the thing with Bauchers is that the bit is extremely stable in the mouth and some horses reallllllyyyyy like that.
Here's a link to a sticky with lots of great bit info that might give you some great ideas: Bit Information (Snaffle and English-Type Bits)
And remember, it often takes a horse 3 rides to get comfortable, settle, and make up their mind about a new bit so no worries if he acts a little unhappy the first ride, just stay gentle and soft and try it out again the next ride.
Good luck! And props for getting out of that TT. :)