maybe i got a bit over zealous but i went ahead and built this up on perf board since the bread board version was working so well. i finally understand what you mean by:
a good idea might be to at least incorporate some sort of request byte from the host computer for each packet of 16 bytes received from the Arduino.
this threw me for a loop for a while, i'm looking at the arduini2max patch now to see how it sends those requests and if any of it is relevant.
here is a pic of my board setup:
and one of it working in MAX