I think TT has players ranked in tiers. He takes the player at a position of need in each tier. All players in each tier are ranked the same.
For example, take for our 1st rounder.
TT has two tiers:
First Tier - Players left at 30: Derrick Havery DE, DeSean Jackson WR,
Second Tier - Players Left at 30: Antoine Cason CB, Sam Baker OT
In this scenario:
The Packers would select Harvey or Jackson with pick 30 because they are ranked in a higher tier than Cason or Baker, even though CB an O line are apparent needs and DE and WR are not.
If a first tier CB, like Rodgers-Cromartie was available at 30, the Pack would take him because he is in the first tier, at a position of need.
The Pack take the best player available. If two equally ranked players are available, the Pack take the one at a position of need.