I've got a couple of inkbird PIDs that I use regularly. I haven't had any issues with either. You'll want around a 6" thermocouple, and an SSID with a heat sink to handle the load circuit.
One of the lovable quirks about the 88!
If he hasn't already, cleaning and greasing the sear surfaces helps. DO NOT TAKE APART THE TRIGGER ASSEMBLY!!!
Because of the difficulty in assembling everything again, a trigger job is going to be pretty spendy. They can usually be brought down to...
Hornady makes a brass headspace comparator kit that works well. Measure the brass that chambers easily against brass that does not. Then it's just a matter of die adjustment.
If you are already getting heavy cam-over with your press and still need to bump the shoulder more, you can get...
22-250 shoulder is 1.515, 22cm shoulder is 1.49.
While the difference is only .025, it's better to set back .06 or so (1 turn on a tikka), so you can true up any runout in the factory chamber.
Not as simple as just running a reamer in there.