How zoo can you make your zoo before you end up getting board wiped all the time? 

This much. I think. The sad thing about this deck is having to run galakrond in place of other cards. It does allow kronx to make your zoo super strong or save yourself. I ran these two because I don't know wether or not you would still get the invoke if you don't have galakrond in your deck. If it still works you can run cult leader instead of galakrond or kronx.

Please let me know the answer in the comments and thanks.