Hypter,
I'm using a Saito 72 on my UCD 46 with an APC 14x4W prop. The CG is 6 inches back from the leading edge. Mine needs 30% nitro fuel to obtain decent acceleration out a hover.

The plane was assembled using the stock hardware that came with it. I used standard Futaba S3004 servos instead of those heavy weight hundred-dollar digital servos recomended in the instruction manual. The 600MaH battery is located in the rear of the radio compartment per the manual.

The plane weighed 6.5 pounds on a baby scale. When I saw that weight I started muttering all kinds of obscenities because the advertised weight range is 5lbs to 5lbs, 10 oz. Maybe my UCD was manufactured with heavier wood to alleviate problems that some people had with wing failure and the fuselage crushing underneath the stabilizer.

Anyway, I'm very pleased with the way it flies.