@Phaedrux I did read the fire safety section on the wiki before my original post. That was part of my justification for using a relay cutoff. I wanted to keep the option of shutting down the dc power supply and I was looking at using a 24v relay (which I already have several) vs a 5v relay. The 24v relays I have available can be mounted in a relay base and have screw terminals. I am mainly looking at ease of use and parts on hand.
@dc42 Thank you for the confirmation. Setting a limit and disabling the output above that limit seems like a simpler approach to the same goal.
@Danal I did find some additional options for thermal cutoffs. I was initially only searching "thermal fuse" which gave me only oneshot devices. After searching for "thermal cutoff" or "thermal switch" I found some self resetting options, but most of them seem to go from 90-100c to 200c with very little in between. If I find something in the 110-120c I'll definitely add one.
Thanks again to everyone who gave input, I'll take it all into consideration during the build.