Don't want to contradict Rossco, because he has a ton of experience, (but I'm about to do so) regarding CG on this aircraft, but as the Ka6, Ka8, ASK18, etc. all have a straight leading edge with a swept-forward trailing edge, the effect is that of a swept-forward wing. In other words, the C of G is further forward than it would be on a wing where the spar sticks out at 90 degrees from the fuselage and the tip rib is nicely in line with the root rib. I've seen a couple of scary maiden flights on ASK-18's where they were balanced at 33% because that is the rule-of-thumb, and it is close to unworkable. For the forward swept wing, I would start at about 28% and work back as you fly the plane and become comfortable with it. Nose heavy works....tail heavy potentially becomes a bag of balsa.
Try this CG calculator when you get your plane:
CG is not a function of airfoil, it is a function of planform, and this will give you a head start on a successful first flight.