operating a VM/LM combo reflux

[pynys pub]

I've been operating my beer keg boiler ,thumper still for the last 3 yrs. now deciding to move on to a LM/VM column reflux . So I've read lots of reading but my questions are unique .
1 - I have a thermometer probe inserted under one of my slant plates for the LM side. Do I need another thermometer probe for the VM side? If so, where would I weld in a coupling? Before or after the globe valve?
2 - I was told that collecting on the LM side before switching to the VM side is just for collecting heads. So when I finish collecting the heads on the LM side, do I shut the chilling water off on the LM side and just run water on the VM side or do I continue to run the water to the upper condenser on the LM side?

I've got a pretty good feeling what needs to be done but would rather ask for much valued experience. Looking forward to a response.

Thank you.