Why didn't me and my bête noire keep our big gaping maws shut?
OK... I should stipulate that I didn't put your gearlist together in my head before I wrote my post -- and I had to do some careful research (using my favorite methodology: reading eBay postings quoting sales lit) just to educate myself about the PCI-424 and it still didn't include detailed synch info (damn that eBay seller guy! You'd think all he cared about is selling his damn gear!)
But I can see the complexity of this issue here... it starts getting Chinatown-esque (in my fuzzy mind, anyhow) at the point where the 424 comes into play... even though there seem to be some parallels to my old ADAT/BRC rig (and I feel like the fact I currently have an 828mkII means I SHOULD know something about the 424 just by affinity -- but I don't and more than a little hazy about the implicit w/c ish with it and its interconnected devices.)
Anyhow, me and my bête noire are convinced that you're no rube and that I should just get the heck out of the way and let you get to the important job of sussing out your jitter spec issues without further digression or explanation -- since in that area we've returned to one element of certainty: I have no expertise when it comes to actually interpretting jitter specs or reconciling seemingly disparate specs...
Next time someone waves a red flag in front of this particular bête noire, I think I'll just have a nice picnic by the sidelines and watch... instead of throwing myself under its cruel and uncaring hooves...