Hitec 5625 or 5645 metal gear digital is perfect for this application.
futaba and JR are expensive in this range.
I would also reccomend metal gear digitals on all the control surfaces
at least 120+ oz in. If you are planning to do 3D

I had a 7lb Yak with a 1.20 and it was perfect for that size plane.
you might want to go with a 1.60 if you are planning to 3D and want
unlimited vertical performance.