Replying to Another ski length thread

Sorry to making another ski length thread, I really need some help to choose what size I need . I am going to buy some ON3P kartel 98 for park. There is a pretty big rocker. I am 5'11 and 150lbs and I am a decent skier, straight 3,5,7 with grab cork 3 and 5. on rail I can 2 and 4 out both ways and front swap. So now you know my level I dont know which one to buy between the 176cm and the 181cm, everybody is telling me to buy the 181 but im scared that there will be a too big difference with my other skis which was 169cm but I dont want the 176 to be too short because of the rocker...help please