I have the standard Brolga Prop and sorry but I can't remember which pitch blocks are in it, but it is the standard setup. All my flying is at about 50 to 53 knots at around 5200rpm one up, or up to 5600 at max weight.
Another (more) experienced Drifter pilot suggested that with the extra battens, the wing has a "thicker" wing profile whereas the standard wing is "thinner". (Between the top battens, the top surface is lower on the standard setup. The more battens reduces the "low" points.)
Also when you look at Franks wing, the Battens act like "fences" helping the airflow.
Kiwi