everyone will have their opinions and I have found that I get the best 3d performance out of a xoar 19x8 laminated or a vvrc 20x6 prop on my DLE 30 but a lot depends on the weight of the plane , engine break in and tune . It takes a couple gallons of fuel through a DLE 30 before they start performing at their peak . So get it broke in good before you start working it too hard , also projected RPM s aren't everything, it usually takes some testing to find the just right prop for an airframe engine combo . Dropping down to a 17x8 may help but the engine is very capable of turning a bigger prop.