level resource dependant activities?

I am finding it difficult to level resource dependent activities.  There are basically 3 roles and 3 resource assignments per activity within the project, a PREPARE, a CHECK and an APPROVE role.  I'm not sure there is an advantage to utilizing resource dependent, when each resource should occur in series, vice parallel.  At this point, to properly generate a more accurate duration for the activity itself, I am having to assign the duration of the PREPARE as a lag to the CHECK resource.  And the duration of both the PREPARE and CHECK as a lag to the resource of the