After 6 months of working up the courage, a pair of tel-trus in the WSM (pre-2008 they didn't have inbuilt thermometers) and one touch platinum.
I had to drill a 22mm hole in the lids - I used a step drill bit http://www.amazon.co.uk/gp/product/B0015NPPCY/ref=oss_product to drill the hole. I masked off the area to "prevent chipping" for the first one but that didn't make any difference. Dripping WD40 onto the drill while drilling was what worked to create a clean hole. I touched up the area after with high temperature paint so it won't rust.
I checked all my thermometers against boiling water just to see - should be 212F
- Maverick ET-72 (mark 1): 212 (both probes)
- Thermapen: 211.5
- Both tel-trus: Exactly 220F
So the new thermometers are out by the same amount - 8F. They're not re-calibratable so I'll just have to compensate. They look nice though.
Photos:
Drilled holes
IMG_0451 by Copsey, on Flickr
IMG_0450 by Copsey, on Flickr
IMG_0448 by Copsey, on Flickr
Installed thermomters
IMG_0452 by Copsey, on Flickr
IMG_0454 by Copsey, on Flickr
IMG_0453 by Copsey, on Flickr