This goes back a long way but I well recall spinning under the hood on Wirraways (Australian edition of the Harvard but more vicious wing drops).
Cage both AH and DG. Enter spin. After several turns (QFI said when) full opposite rudder and stick going forward. Concentrate on the Turn and Balance Indicator and watch for it to flick back through neutral (for want of a better term). Immediately the bat (of Bat and Ball genre) went through neutral, centralise the rudder and ease out of dive. You had to watch the Bat carefully while pulling out of dive, though - because if it still showed a slight rate of turn and you applied significant "G" the G force would act on the Bat and make it show a further rate of turn. So best to unload slightly during the pull-out if you suspected the Bat was misleading you. Keep Bat central during pull-out by use of appropriate aileron.
During the pull-out you kept a close eye on the ASI and as soon as it stopped increasing (from the recovery dive) you knew you were in level flight or close enough. Did several spins in Mustangs which wiped off lots of height, but fortunately never in IMC.
That was the beauty of the old fashioned Bat and Ball Indicator - (also known as Turn and Bank Indicator or Turn and Balance Indicator) it was practically fool-proof. Not so the Turn Coordinator which has an angled gyro wheel that can furnish erroneous indications if well beyond a rate one balanced turn.
The Turn-Coordinator I believe was never designed for anything but a rate one turn so relying on that for interpretation of spin direction and IMC recovery would be bad news.
I am only guessing now, but if by mis-chance I was in an IMC spin in an aircraft with a Turn Coordinator, then I would release all controls including rudder and hope that the aircraft would recover without my input. Some aircraft will do that providing you let go of the lot (don't forget to ensure throttle closed, of course) as soon as you realise you are are in an unusual attitude.