Most composers that I know who use Logic and VEP 6 are not using the Multi-Timbral plugin version (And these are primetime players). They all use the Stereo plugin and have one VST/AU instrument per VEP 6 instance/window (window is probably a better term to use since VEP 6 came out).
One stereo signal comes back from each VEP 6 window and is mixed directly in the instrument channel strip (no auxes). No disabled I/O plugins are used at all because they are not needed. Everything times out perfectly.
It is a REALLY great method as long as everything connects....when instances don't connect for whatever reason, it is a big problem. Hopefully the other gigabit swtich I ordered will make the difference.