If I had 2 Catchers for each level would it be better to have them distributed like this:

AAA: 1, 2
AA: 3,4
HiA:  5,6
LowA: 7,8

Where 2, 4, 6, 8 are the backup and get little on field time ..

OR

AAA: 1, 5
AA:  2, 6
HiA: 3, 7
LoA: 4, 8

Where the four best prospects are getting major playing time at different levels and the backups are not expected to play except in an emergency.

Asked another way, is playing time more important than the difference between coaches at the different levels in the organization?

I'd want my best guys to play.   But you have to assign players to the proper level based on age/experience.   If you have two 22 y/o catchers with 4 years experience and they're your best, I'd probably have one at C, the other at DH/RF in AAA.

No one is completely sure what has the most effect, playing time vs. coaches, but, as I said, age/experience should be determining the level.