Just a little tip from the n00b all-grainer:
I don't have an insulated mash tun, since I'm going BIAB. I found that by wrapping the kettle in a blanket during the mash, I was able to hold my temp VERY steady over the course of an hour. My thermometer moved maybe 1-2°F over that time, whereas my first BIAB just sat with the lid on over the stove and dropped a good 15°F or more over that same time period. Not sure what your setup is, but hope that can help.
I don't have an insulated mash tun, since I'm going BIAB. I found that by wrapping the kettle in a blanket during the mash, I was able to hold my temp VERY steady over the course of an hour. My thermometer moved maybe 1-2°F over that time, whereas my first BIAB just sat with the lid on over the stove and dropped a good 15°F or more over that same time period. Not sure what your setup is, but hope that can help.