It's good to see you have found the challenge with the pump tach sensor.
A comment that Kibbler made to me was, by monitoring and controlling your system by your water temps, as water temps change slowly,
as opposed to air temps which can and do change rapidly.
You can stop the constant on/off cycle you get when only monitoring air.
How is your system being monitored by air or water?

As to the dual loop, looks like you just found a good reason to re-build

Are the above temps at idle?