Split backs and zone

I posted this on another category, but thought here would be more appropriate. Has anyone tried running iz and oz from split backs under the center. We run it from gun, but we are trying to do it from under the center this year and I want to know what you guys think. Specifically, if you have done this, QB footwork as well as RB footwork. We usually have our backs at 4 yards depth (fly offense) when under the center, but we have been toying with 5 yds. Is this deep enough for iz and oz? It is when we are in gun, but we have yet to see if this is deep enough for under center. Any responses would be appreciated.