Regional discussion and conditions reports for Canada and Alaska. Please post partners requests and trip plans in the Canada and Alaska Climbing Partners forum.
I would want to say better success rates on Huntington although the Tokositna can have terrible weather too.
If you go to Huntington you will have two other classics laying in front of you in addition to the Harvard:
West Face
French Ridge
If you go to Denali you may be sitting at 14k on the Butt for awhile with secondary options such as:
West Butt
Cutoff
Rib
Tough call - been to both places and had rough weather each time. I guess what ever allows the best plan "B" would be my recommendation. The Cassin, simply put, is a waiting game. How long are you willing to wait is the question. If your prepared to ride out 2+ weeks of weather you will get your window. Easier said than done though.
EDIT: It will be fun either way though! Best of luck!