excel 2010 customize the ribbon

[already]

Hi

I have made a custom ribbon in excel 2010. But when this ribbon is loaded on a 17" screen it is not the same as on a 22" screen.
So if I have buttons with the same 'importance' some are greater than the others and I want the buttons with the same importance in the same size.
How can I solve this problem?

Another question is: can I use customized pictures/icons in the ribbon without using ribbonX?

Thanks in advance for your help

Kind regards

Al