Where are you staying? SLC or Park City or somewhere else? Most people pick a place to stay, then line up ski areas to visit from there. 8 ski days is a nice long visit, esp if you take a rest day somewhere in there. You're gonna win whatever you do, but assuming you stay in Park City I guess I'd drop one of the Snowbasin days to lessen the commuting. If you stay in SLC near Alta/Bird I'd drop one of the Park City or Snowbasin days.
If you're gonna move around and sleep in a different place every few days, then I guess I'd drop one of the Park City or Canyons days, but I've been to those two and Snowbasin would be novel to me so my perspective might be warped.