There is no elegant way to switch from pre/post to stereo.
You will have to essentially re-wire your chain by hand, as well as make some changes in the H9 control software.
BUT.. I think it is a hard reality that some of the effects belong in the effects lop, and some belong at the start of the chain.
That said- your Musiccomb has some stereo loops, no? Could it handle all your pre/post routing? Probably too complicated.
