i use the 183's as my park ski. i'm 5'11" 180-190. they are the best. such an awesome one ski quiver. they are the perfect east coast ski, no doubt. you'll be stoked.
as far as what length you want, that's personal preference. like i said, i have the longer ones and they're my park skis. don't be afraid of the 183's. they are not hard to handle. but if you like shorter sticks, you may be happier with the 178's. it's up to you.