Have 14 now and will likely go to 16, as people who come to the games with us as guests tend to have a great time tailgating and even in the games.  Donation will simply be a function of the # of tickets in 224, which requires seat donations - we're comfortably in yellow, so likely no reason to go much beyond the current donation, especially since my company won't match athletic donations.  This means that once I reach enough for the parking passes, my additional donations are academic in nature, maximizing the donation, via the company match.  
All of this is independent of who the coach is.  Wanted Flood fired 2 years ago and again, upon hearing the details of email-gate (not to mention the loss of discipline on the team), but maybe it's because I'm a 3-time alum, but I dont want to do anything to hurt the program, so I'll continue to support the program and let my dissatisfaction be known in other ways.  I also have the long view on this and am hopeful that things will get better as the B1G $$ starts rolling in.