Well, the OP has to start somewhere in his shopping.
If he wants to do an equal mix of park/groomers/glades then he'll want a mid-wide twin-tip. A noob skier will want a shorter ski, but if the ski is rockered then the effective edge is short and it skis like a shorter ski than the measured length and he can therefore go longer.
At his height, weight, experience, and goals a 163 would feel way too short and a 187 would probably feel way too long, hence my suggestion of 177. It's a starting point.