Lol... I just cram the meter into my cables... It's an el-cheapo automotive multimeter and I use it for tons of stuff. I'm with graham and only like to use temp sensors during setup, not once I have a setup tuned. Usually I'll just feel the fin with my finger while I'm going up monster hills or over-revving and I can tell if it's getting close to too hot or way too hot. I've almost had accidents looking at temp sensors before in traffic and by reaching down to feel it I don't have to look away from the road.
I've cut down on the metal mass from the picture above (removed the bolt from the thermocouple and decreased the amount of solder in the terminal crimp end), but even with the reduced mass, it's still more thermal mass to heat than a trailtech. You'll know if you're in the too hot ballpark though and that's all I wanted. The sensor was within 2 degrees of what I expected in the oven and boiling water, so I feel like worst case scenario with the increased mass it's 10*F low. I'll have to compare to someone with a trailtech at a rally. It'll for sure tell you if you're in the ball park - and that's all you really need.
It's just a large copper electrical terminal + plumbing solder + amazon thermocouple.
I've used it to play around with how much timing I can get away with on my derbi and as a verification of temps on my vespa.
Completely repairable, re-usable, more widespread and available. You end up with more function for your money too IMO. You can weld up bungs with compression fittings and use them for EGT too. (edited)