This usually works. Can you try what happens if you disable the CC and the "Keyboard shortcuts" plugin? (Then restart, then try again with the settings...)
Strictly speaking, with 10.05 this was a no-go. While the Keyboard Shortcuts plugin does go away quietly, the Cccc plugin (if that is the one you meant) reasserts and reenables itself after a crash.
However, a devious workaround was found. Since CB take forever and a day to start up, there is an instant midway thru the process when the menus are up and running, but the main window has not appeared. If you can catch the instant, the Settings/Editor window will pop up, the General Settings pane will work and you can fiddle with the Choose fonts button and popup window. Then, when you apply the changes with Ok, the main window will appear and the font settings will be honored. Plus, when you quit and return, the changes will still be there. Woe befall you if CB should crash, however, cause all will revert to the original icky mini-font & size. Don't know if disabling the Keyboard Shortcuts plugin helped, but subjectively it appears to take a tad longer to load, giving you a little extra edge to have success with this workaround.
Oh, and closing the main window to carry out the adjustments is a no-go since CB will misinterpret your closing of the window as a synonym for quitting and exit normally.
Will try out the nightly build...