AIX Pitfalls when upgrading from 5.8 to 6.0

We are upgrading from a 5.8.3 environment to 6.0.1. Moving to completely new hardware and fresh copy of AIX (with required run level).

We have a ton of cron jobs running tcl scripts and want to make sure all of these scripts run perfectly after we switch over to 6.0.1 live.

Does anyone have any advice, pitfalls, horror stories, etc that your willing to share?

Does anyone have a good methodology for testing these scripts without live data?