ISBoxer Character Set XML File Question

So I have been using ISBoxer for a couple of weeks now and I have a question for others using the app. WIth your character sets do you just keep adding to the same xml file or do you use a new one for each set of characters?
In my usage to date I have used a new xml file for each new team I setup.
How are you guys doing it? What are the pros and cons?
Thanks for any insight :)

I use one XML file that way if I come up with a cool keymap I do not have to copy and paste it to the new XML.

I use the single file.

Sometimes I want a key to work one way for one team, and to work the normal/default way for every other team. Example D, in my guide shows how I achieve this.

Pretty much just customize as I go, but back it up too, just in case I mess something up. I'll have several previous versions that worked fine.

I think I will start using the single file then, seems like it is the better way to do things unless I want to dump all previous work :)