Shortcode parameters modification

I have alot of galleries in posts, which inserted to the posts directly by shortcodes. Right now I’m making wide modification of the gallery views and some settings changes take alot of time. I have decide to modify shortcode to insert there additional parameters which could be easily switch in gallery shortcode.
I have spend few days, but can’t find proper way for such modifications. do you have some kind of developer guide for your gallery ? with such instructions?