I wrote:

you should be able to log into your account on the  ClimatePrediction (CP)
website, and allocate your desired percentages to  your selected projects.

. Open your Boinc client
. Click the Projects tab
. Click the Your account button, which opens a CP webpage
. Under "Preferences," click on "View or Edit climateprediction.net 
preferences (control resource share and customize graphics)
. Next window, displays preferences.  Link for actually editing is at the 
bottom of the page.