Best Failover mode for AIX?

On the Unity platform, what is the recommended initiator failover mode for AIX when PowerPath is not being used?  The Host Connectivity Guide specifically calls out mode 3 for PowerPath but it does not have guidance for AIX native MPIO.

We tried ALUA (mode 4) but the AIX host was seeing multiple instances of each LUN, even after ODM installation.  We switched to mode 1 (Passive Not-Ready) which fixed that issue.  Now we have certain hosts which are dropping their second FC login to the Unity (one initiator remains logged-in; the other drops offline).  The Fibre Channel switch continues to see both initiators as active but the Unity only sees one.

Any thoughts or guidance?