Can I change the default values for buttons?

Hi there!

I was wondering if I could change the default settings for the GenerateBlock buttons block. For example, the default padding is 15/20/15/20 and I would like that to be 15/15/15/15. I would also like the default width to be 100% and the content to be align center. Finally, I would like to change the default hover color. I tried changing it under Customize -> Colors -> Buttons -> Background, but it still defaults to a shade of black.

Thanks!