After much reading, and a couple of posts, I decided to go with inexpensive units.
I got 2 - F&C, 2" thermometers, with 3" stems, off of eBay, both delivered for $20.58. The units come with a wing nut for mounting.
The required hole is larger then the 1/4" claimed. I marked the holes with blue tape, drilled a 1/4" pilot hole, then a slightly larger hole and reamed it a bit until the stem fit tightly.
I tested them in boiling water when I got them, and they are accurate. I haven't tested them on a cook yet.
They do look good.
On my 22 1/2" WSM.
On my 18 1/2" WSM.