What prop pitch lends itself to better to 3D flying.

One of my favorite airplanes is my Hog Bipe I built from a Sig kit. It has an OS 91 four cycle and a 14x6 prop. I've been flying it for 5 years now.

I've started to get real aggressive with it but I just can seem to get it to hover. I can hold a hover for a little but it has to be at full throttle. Any wind can blow it off and I just don'y have the power to pull out or correct.
I realize the control surfaces are not big but I thought a different prop might change the air flow and give me more control.

Should I change to a larger diameter and lower pitch or a smaller diameter with a higher pitch.

Any Hog Bipe fans out there.

I also have a new OS v95 four cycle but don't know if there is much power difference between the two.