Blazer,
The airplane has NOTHING to do with the prop, it's the engine. Which engine? If I remember correctly, this is the Saito 1.00, isn't it? If so, then I wouldn't use the 14X6, as I'm afraid you will unwind the engine too much in the air. That thing will probably pull over 10 grand on that prop static. In the air, you are going to unwind beyond manufacturers recommendations. You can try it, but I would caution you to be careful and not let the engine rev too high. You might even program your throttle servo to not go to full throttle. This will keep your RPM's down to a reasonable level. Having said that, I would go with the 15X6 prop if you are concerned about landing speed. However, I've never had a problem slowing my saito 100's down with a 14 X 8 prop. Remember, four strokes spool down faster than two strokes, so when you reduce the power, the prop will almost immediately slow down. Also, this engine will idle very low if you tune it right.
Good luck.