A lot of games have an additional game version in steam to test unstable patches and try them out. I know there is a way to manage this problem, like copy your DayZ folder, name them DayZ_Exp and DayZ_Stable, delete local content and rename the folder u want to play right now to DayZ and install game on steam.

But this workaround is exhausting and a lot of people actually dont know this. Also u need to copy the folder again if a little patch comes out with a new update.

So my suggestion is to add an extra steam version for dayz-experimental. Then u can choose what u want to play in your steam library. Think about the time when no exp servers are up but u want to play. With this solution u can easy switch to stable and play a little bit until exp servers come back online. Also u dont need to download things around cause u have two versions rdy to play. Screenshot attached of another game which is using this method
http://imgur.com/sTeB6vZ {F31769}