New to 912- CHT questions

Greetings,

I have an older 912UL I'm installing, and I'm in the process of planning the Dynon D-180 installation.   This is the first 912 I've installed, so I'm learning as I go.   I will install 4 EGT probes, and would like to have 4 CHT readings, but know the 912 only has two designated CHT locations.  My engine has the older style dry probe locations, which use a resistive temp sensor.  As I understand, you are typically supposed to monitor the hottest of the two, which will vary depending on the engine installation (tractor vs pusher).  I also understand that these CHT temps are really closer to coolant temp readings than traditional CHTs.  If any of that is wrong, please let me know. 

I will of course monitor the designated CHT locations, since there are specs for that.  I'm very tempted to also add ring type CHT probes for each cylinder.  In several past threads, I've seen statements such as "never use ring type sensors under the spark plug", but when someone asks why not, there is never an answer.  Is there really a reason not to use them, or is it just considered unnecessary? 

I'd rather over-monitor than under-monitor, so I'll likely try to add a real coolant temp as well. 

Thanks,

Rusty