I don't have a need for it since I'm building my donation out of the custom fields - any way to disable that completely? I only see "User Input, Pre-set, or Both" as options.
The custom fields can not actually calculate any final donation amount... not at this time anyway. So you have to have SOMETHING for entering an amount. Sounds like you should set it to "User-Input" then there will just be one input field for giving the amount... no radio buttons for other options.