For mounting the temp probe at the output of the coil, I ended up soldering together pieces of copper and making a small chamber that I could screw it into.
My coil is connected to 1/2" copper pipe to make long arms that come up and out of the HLT. One of them is just "J" shaped 1/2" that ends in a garden hose conenctor. The other expands to 3/4" and has a Tee in it with the temp probe going through one part of the Tee and the downward partt of the Tee ending in another garden hose connector.
You can see it in this pic.
PS: You don't really need to put a temp probe in the BK unless you want to monitor the temp in the kettle as you chill. The temp probe there won't help you in any way with the actual boiling.