That is understandable, but zombie maps for me should be progressively difficult. Start off slow and easy before becoming a struggle as you try to advance towards power and jug.
This is just a personal opinion though. My affinity for the Treyarch maps means I prefer my custom maps to be like wise in terms of balance and style.
Again, this is not a dig at yourself or your map. I can fully understand your reasons for adding them. Lower rounds can be very slow.