140L's yield great performance when operating in the low to mid 8K rpm range. Given that variables such as air density, nitro level, airframe drag and airframe weight will be the guiding force that determines what works best for you. Below are a few APC sizes you may want to consider for pattern application that I have had good results with.

Size
15x12
15.5x12
15.5x11.5W
15.5x12W
16x12
16.5x12N
17x10N

Glen
http://www.geocities.com/rcprecision/pah.html