Hi Bert
No problem. it is not easy to wrap your head around things like the prop loading. The issue for most is to find the balance between what is good for your aircraft to fly well and at the same time give you long engine life.
The slower flying STOL aircraft have a much smaller envelop of usable RPM, I think that is understood. What that says is your static, take-off roll and even into climb will see very little change. Simply speaking the speed difference is so small that the blade has only a small change in the angle of attack. Faster aircraft are going to react far differently in that the forward speed is so much different. the blades "unload" as you move faster. I get it, the design is great for STOL performance and for most that is exactly why they love the plane.
So If I understand you correctly the question is what is the most important since no matter what we do in this case is make a compromise. I don't know the engine serial number you have, yes that might affect my answer. if you have an engine made before 2006, one with a continuous serial number stamped into the crankcase (down between the number 2 and 4 pushrod areas, you have the old version case. If your engine was a case where they split the number, starting with 06.0010, then you have the newer generation case. (at that time crankcase numbers were changed to have the year 06 with a dot . the balance of the number is the serial within that year. so 96,07,08 and so on for year. The rest is 0010, 0011, 0012 and so on up to whatever was made within that year run.
On the old cases I would prefer to see the 5200 used if that is the heaviest loading. if for example you are going to climb a lot and fly a lot of time in climb configuration where the case is at its highest stress levels 5200 is much better than 5000. Dont worry about an occasional thing here, we are talking about the general characteristics that the aircraft operates in. While 5500 is max continuous I would not sweat 5650 or even 5700 as you said can happen in level flight. This range of RPM will give you the best life of the crankcase. On fast aircraft they used to fail due to people setting the pitch to less than 5200 WOT in level flight. The idea was to get great crusie and low fuel burn, it did not work by the way. Glider tug aircraft would also fail the case with extreme loading by full power climb followed by full off throttle dive back to the airport to tug another glider.....600 to 800 hours later the case is shot and it is an expensive repair.
Now in the event you have the newer crankcase i would not be as concerned about climb being just below 5200,, the internal changes are very major and we no longer see case failures since that change in 2006. The WOT at level flight can be controlled by your throttle , however the security of the prop acting like a governor to control overspeed is gone. Obviously control cable failure is not common (of the mechanical linkage some use) so this is unlikely in most cases.
All things considered in a STOL aircraft I would say it is better to get over the trees and have a short take-off. The risks of overspeed can most likely be managed in other ways as you have already pointed out. That magic 5200 is the peak torque point of the engine (actually it is 5252 but don't worry about the small error) Everything from 5200 to 5800 is building HP. Limit any time over 5500 to less than 5 mins. in a dive, or even small pitch changes, RPM can climb up quickly. So if you can cruise at 75% power, that is 5000, you save a lot of fuel and have lots of room to maintain control with pitch change. The engine as you know loves 5000 and up for performance. As for the climb performance RPM will be affected by the forward speed. in a STOL that might be very slow however.
Not sure that helps, just my opinions on what is best for the engine.
Cheers
