I agree with Jody, we saw aprox. 600 rpm drop on my friends DL50, going
from Vess 22b@7200 to 23B@6600 aprox., larger prop would just overheat
the engine and it would be out of the power range IMO.
From what I have observed the DL appears to have a higher rpm power
curve, wich is fine for low weight aerobatic planes.
I think higher compression engines with a higher low rpm torque curve, like
the 3W55 or ZDZ60 would turn the bigger props easier.

MY 2ct. Allen