BC- i do it in post when i have a couple jb3's at hand some nites, and transfer them going jb3>jb3 via a 4pin>4pin firewire cable, and do the matrix in wavelab 5.0's audio montage
quite easy w/ no delay, i try to make sure they are aligned every 40-60 mins, pretty damn easy once ya do it a few times, took me 6+ months to learn how to do the first one tho