Back when I got my 75AX it was in the upper 90s for a month. I did about a weeks worth of swapping props around to see what it liked best while I dialed in the new airplane. One test was the "unlimited vertical" test. Timing the vertical climb until the model stops climbing. (Virginia, no there isn't a Santa, and there are very few models with unlimited vertical.) Turns out the engine/airplane would go 10seconds with a bunch of different props. There happens to be lots more tests I do when I'm testing props, but the limit of vertical one seems to grab most people the hardest. And 10 seconds is a good time, because thankfully, the model is still within sight.

Anyway, one prop I happened to try was still going decently strong at 10 seconds. Usually got to 11.something. Here's a picture of it.

BTW, during the week of tests, the DensityAltitude was between 3,250 and 3,520 the entire time. Close enough to consider all test days as relatively significant.

I also tried a 12x6(3) and it allowed the engine to run past what must have been optimum rpm in the air.

The 12x8(3) in the picture works better on our grass field than the engines next favorite prop (and EVO 14x6). The 2blade 14x6 did the vertical every time just over 10sec. So for some reason the MA12x8(3) seemed to have hit the sweet spot for that engine. If you have the chance to try one, it wouldn't be wasted money. I also use 10%nitro fuel. Never saw a reason to run higher nitro for what I do. This winter, the 3blade is pulling even better, but I haven't bothered to put a watch on any climb, nor have I even tached it. In the summer it tached a couple hundred over 9k on the ground when needled to fly (not max ground rpm for tach wars, but set to fly without meltdown).