[Lizard]

OmniPlan 2.0: As we've mentioned elsewhere on this forum, that time is probably best measured in months, but we're really not certain.

Scheduling Backwards: you can accomplish most of the same thing if you create dependencies from the tasks & milestones to the final milestone with the appropriate lag times. If you lock the start date of the final milestone, then the preceding tasks won't move the final milestone if they run out of time. Instead, they'll create a violation.