youre 165cm so that points to 171, but the skier's weight should always be considered in ski length decisions. and vishnus are very soft and forgiving and don't have a long effective edge
how experienced are you at skiing? what have you been on before, and what length?
honestly i think if i were you my first pick would be 171 Wet Plus (theyre just stiffer, right?) because 6cm over your head is plenty on a park ski, and the stiffness will help keep you stable. you need to keep that weight supported but you don't want skis straight up towering over your head for park and rails and shit haha