Don't preset the Milestone owner in the template
We use milestones within our schedules on zoho projects as Key MUST DO tasks and they are always for someone different. The templates only allow you to set this for someone specific meaning that the project owner always has to go through and change these when setting a new project up. This is quite a time killer and I suggest that the Milestone owner is set as part of the set up when the owner is selected from the list.