Hammered paint looks like it's rougher than it is. There is some roughness but it also adds a lot of thickness.

If you're looking at making this into an official paper then I would suggest that you stick with the electric motor and only use one motor for all the experimental series and one type of prop for each series with varying turbulators.

Also the need for turbulation depends on what the airflow around the prop is like. If the airflow is clean with no separation then adding turbulation in the form of dimples or trip threads is going to hurt and not help. Adding dimples on their own does NOT reduce drag. It's the effect they MAY have on encouraging the air to stay in contact with the surfaces longer rather than pull away in a drag producing separation bubble.

It's the same with the golf ball. The ball tries to make the air flow around a very short curve. At some point the air can't remain stuck and it pulls away and forms a turbulent wake. This is the separation point. The dimples act to provide a source of turbulation to the boundry layer that encourages the air to remain conformal to the ball shape for a longer time. Not to the point where it joins at the rear but significantly longer than a smooth ball would allow. With the dimples a much smaller cross section turbulent wake is the result. It is this smaller wake that provides the reduced drag. Even on the golf ball the dimples ADD DRAG but the drag they help to eliminate more than makes up for the direct dimple drag.

So be sure you're doing this for the right reasons and do not be surprised at all when a lot of the lower pitch props produce no gain and in fact show a loss with the addition of dimples or threads or yak hair stuck on the blades. But there will be one prop that showed itself to have a much higher need for power where the pitch increased just beyond what the air could stick to in a static situation. THAT prop will gain in the static testing by having a turbulator of some form added to it. But that same prop in the air would have seen a reduction in angle of attack as the speed came up and may have gone back to no separated operation.

I saw and heard this when I tested a mitt full of props on electric motors a bunch of years ago. Low pitch props wound up like crazy and drew little current and had a sizzle to the sound. High pitch props didn't produce a lot of rpm, drew mondo current and sounded "fluffly". But some of these "fluffly" props on a higher speed sport model proved to work well. You could hear then unload in the air and the revs jump.