let the A/P take the strain
"whether folks are happy to undertake prolonged single pilot IMC flying without an autopilot or would never consider it?"
Never. That would just be soooooo unpleasant!
I wouldn't even consider it.
What's more I might spill the G+T!
Non-functional A/P means I do not go IMC.
For me in the rough stuff the A/P does a far better job than I.
IFR - I hand fly 5 mins on departure and 5 mins on approach/landing.
Safer for me to monitor what is happening.
If I want to hand fly I take my R44 instead - and I never take that into IMC.
SB