Keeping Edited theme for new users on wordpress mu ?

Hello,

I really like this theme and the simplicity to change the layout.
I have recently added it to wordpress mu and have changed the layout to my specifications.
I would like to keep this layout everywhere when new users sign up for a new blog.
However when a new user registers, ata loads with the original format.

I realize I have to hardcode some files, but how do i do that ?

THanks