Cam Install: To Advance, To Retard, or Shoot for Straight Up?

On mine I "centerlined" my cam which is the same as "straight up". That said any changes in timing advance or retard with the distributer (vacuum or mechanical) are equal in affect. Think two sine waves on an occilliscope, if they are "straight up" they line up symetrically. If they are out of phase (advanced or retarded) the lines appear out of sync. Overlap, duration affect this also. Centerlined,staight up is the best place to start in my opinion as a baseline. As far as gears I've always used the hd double roller steel not the nylon stockers just cheap insurance in case of tooth loss and valves hit pistons. P.S. cam cards are'nt always exact no matter how you install your cam physically degree it.