I have a KYosho Majestic 1400 as a winter plane and it's powered by 63FZ. My plane is 2,2kg in weight and I use 30% nitro in my fuel. The main interest for me is to keep the fingers moving during the long Finnish winter and not having to reinvent my F3A flying skills every spring.

I have tested diferent propellers and I find 13x6 APC the best. The other options were 12x7 and 12x8. 13x5 might be ok, but the engine will over rev as it is far more lighter to spin in higher speed. I get good power, rapid acceleration and top RPM around 11200rpm on the ground. In the air the plane performs jus the way I prefer. It brakes pretty well and I can get smooth power transition on low corners without having to throttle up in advance.

I think you should give 13x6 a try, you get the same speed the 12x7 gives but benefit from the 'stronger' performance on uplines.