Vic....I don't know if when you say you "apply rudder it does a side slip" you mean that you are only applying rudder and not aileron along with it, but a side slip, ie yaw, is exactly what you would expect for rudder only. Ailerons only bank the airplane and the lower wing loses lift and the plane will start to fall in the direction of the downward wing but this action does not turn the nose of the aircraft towards the turn... As a matter of fact "adverse yaw" tends to turn the nose in the opposite direction of the turn so the rudder is really needed. . As I said in the earlier posting when you're flying full scale it is usually pretty noticeable because if you don't use rudder you feel like you're going to fall our of the side of the plane. If you "coordinate" the turn and get it just right the sum vector of the forces is directly down to your seat and it feels very secure even if the plane is hard turning in a 90 degree bank and directly on it's side. If I'm telling you something you already know so if I am don't be offended...Maybe this plane just needs more rudder or aileron than you are used to with your other planes.
...I would keep trying and experimenting with it's flight characteristics. The airplane is truly unique and brings a lot of comments when you take it to a fly-in. So it's worth it