Paul,

From reading the threads here on RCU, lots of people have used the Magnum 91 FS and still needed 10-12 oz. of dead weight in the nose. Your Saito will probably balance it well without uneeded weight. Swinging that big prop is going to be sweet. And the left stick controls flutter. Hopefully you don't get any!

I also have purchased the Magnum 91FS for this bird but I am having second thoughts about running it direct drive. I am toying with the idea of using a belt driven reduction system I have. Then I could swing a healthy 4-blade prop.