I used to do a lot of teaching in the older Arrows, but it's been a couple years...lemme see if I can remember what we used for power settings...
Steep turns -- 18" MP / 2400 RPM for entry would put us at about 125 mph, well below maneuvering speed...I think maneuvering speed was 134 mph. Use a little less (17") if the OAT is cold or a little more (19" or 20") if it's really hot or you're a little heavy. Roll in to the turn and bump the power up 2, 3, maybe 4 inches to maintain altitude/airspeed.
Slow flight -- 17" MP / 2400 RPM to start with. That should put you into the white arc and you can drop flaps/gear to slow yourself, then adjust power accordingly.
Power off stalls -- 15" MP / 2400 RPM to start with. Configure flaps / gear however you want them, then pull the power to idle and shove the prop forward.
Power on stalls -- 17" MP / 2400 RPM to start with. I always configured the plane with gear extended and two notches of flaps to simulate lifting off out of a short field. As soon as the plane slowed to 80 mph or so (liftoff speed out of a short field) I'd bring the prop forward and set the MP at 22" to simulate a high density altitude takeoff. I think 22" / 2700 RPM corresponds to about 60% or 65% power which is the minimum allowed for "power on" stalls as per the PTS.
Lazy eights -- I can't remember exactly. I want to say 18" MP / 2400 RPM worked pretty well, but it's been a long time.
Chandelles -- Whatever you feel like. A "slow cruise" was what I usually aimed for. Just get below maneuvering speed. I think 18" MP / 2400 RPM worked well for entry.
Steep spiral -- Idle.
Eights on pylons -- Again, a "slow cruise." Probably 19" or 20" MP / 2400 RPM.
Entering the pattern on downwind I'd fly at about 22" or 23" MP / 2400 RPM, but I like to move along fast on downwind. I know a lot of pilots who would chug along at 19" or 20" in the pattern. Even so, the higher setting should still keep you well below 150 mph, the max gear extension speed.
Abeam the numbers on downwind reduce power to 2100 RPM. I think that's about 12" or 13" MP, but it's not like it matters since the prop is off the governor--set the power based on RPM. Then shove the prop forward, extend a notch of flaps, run a pre-landing check, and turn base. This power setting keeps fairly tight patterns.
For normal approaches I'd fly at 90-100 mph, but on short fields I'd roll on to final stabilized at 75-80 mph. Just be careful about getting slow on final. The old Arrows are notoriously impossible to flare if you get slower than about 70-75 mph. You can really plant them on hard if you're coming in steep and slow. You might want to keep the approaches a few knots faster until you get a feel for the plane, then start working your way backwards, towards slower speeds.
I think that covers everything. Hope this helps!