What about running it on a three blade?
Ive seen a few electric pattern planes running 3 blade props, Im assuming its in an attempt to get it to slow down on the downlines.

You might want to talk to Tony Stillman. He has a Brio, and I think hes using the Axi. He should be able to give you some good input. I cant remember if he's running a 2 or 3 blade prop.

Edit:

Dan Landis used a APC 15.75X13 3 blade in the F3A Nats on his Axi 5330/Brio
Here is his set-up
Axi 5330
CC 85HV
Tanic lipo
68 amps at 7800 rpms - 2200 watts
Engine Temp after landing was 148F
Battery Temp was 122F

Scott Anderson uses a APC 18x12E on his Axi 5330/Focus II
Here is his set-up
Axi 5330/10
CC 110HV
MaxAmps 10s2p 4200mah
69 amps at 6250 rpms - 2200 watts
Battery temp was 130F