As somebody who skis almost exclusively in the West (Tahoe, Colorado, Utah, Wyoming) I'll say that a ski in the 95-105mm range is pretty damn near perfect for every day conditions that we get out here. I ski either a 94mm or 99mm as my every day ski. So, i think you can get away with something "that wide" for 50/50 (my Colorado buddies laughed their a$$es off when i was able to lay railroad trenches on my 188 Lib Tech skis, which are 99mm with a 130 tip...this was after they had been telling me that i needed to be on something shorter and skinnier).
honestly, though it really depends on your skill set. the aforementioned buddies of mine in Colo all ski stuff in the 69-88mm range as their every day and pow skis. i think these are way too skinny, but then they rip on them, so who am i too judge?
while not the Bible by any stretch, i find that reading the Gear Guides from Ski, Skiing, Powder, Freeskier, and other magazines can help in narrowing down what you might be interested in trying. When i was in demo mode 5 seasons ago that's what i did. i poured over the magazines and began making a list of the skis that sounded like they fit my bill. then i got out and tried some of them. to me that's the best way to go about it. again, you have to have a pretty clear idea of what you like/want from a ski (do you want an overall stiff ski? do you want a damp ski? do you want a turny ski? do you want something that will float in powder but also rail groomers?). once you can articulate what you like and dislike then narrowing down what skis to try becomes easier.