[Bob Meadows]

Thermostats are generally 87 or 92 degrees:~
Not a great deal will be noticed regarding running temperature but the heater may benefit from the higher one.
Stats normally have the temp reading stamped on them so easy enough to check & remove/replace.
(A head skim is the correct procedure)

Is the radiator and engine block clear of scale or debris? they should benefit from a descent flushing out.

Central heating descaler is a very useful product here- not expensive and goes a long way as it needs diluting.
The product can be used for dissimilar metals so fine for a car.

Bring up to normal temperature and circulation- allow it to work for as long as you can before doing a final flush.
Back flushing is also beneficial particularly for a radiator.
Good Luck.
Bob.