submix a few send this to the MPC
record a number of tracks at the same time (incl. MPC output) to keep the groove intact.
then mix inside the DAW
submix for MPC (same)
mix everything on the Mackie, record the stereo output
minimise the number of AD DA conversions (see here
: once or twice is not going to hurt, but more....
try both and see if you can maximise quality, and the "feel" of the track.
sometimes it's better to mix on a cheap mixer, than ITB, it depends on your skill of both.
then pick the one you like best
extra work but worth the effort I'd say
then post your findings here please