Last year I bought 172mm Blizzard Magnum 8.0ca's (I am 5'10" 175lbs, athletic build) along with new fitted boots for my move to Salt Lake City. Before the season began, I had not skied in 10 years so I classified myself as an intermediate even before I got on the mountain. I was able to get about 25 times with these skis last year at The Canyons. About 70% of my skiing was on steep groomers, either going going as fast as I push myself or carving wide runs, and the rest was black diamond mogul fields and some tree skiing. I think the lighter ski like the magnums were good for learning the bumps since I could change direction quickly with them. Although powder days were few and far between, I was able to feel very comfortable on three to four 8+" days except when the heavy mogul fields developed later in the day.
I loved riding the Blizzards early during the season since they were light and nimble, but by the end of the season I felt like I was overpowering the skis when I was carving the groomers. I don't know if it was because of the length or that they are light ski due to the carbon. Second, I did tend to submarine many times when riding deep wet crud late in the day after big storms. I attribute that to my lack of practice in these conditions, but based on reading these forums I think a longer and wider ski may have helped me.
I plan on keeping the magnums for this upcoming season for groomer days, but I was thinking of trying and buying some demo skis that may help me progress into a more complete skier. Any help on what may suit me best would greatly be appreciated. I think something over 85mm and maybe 178mm would be ideal?