I don't know enough about all this to really help but one thing I'm pretty sure about is that digital devices sound horrible in parallel effects loops because the output of a digital device will almost certainly be out of phase with the straight through amp signal, and the resultant phase cancellation will give you that tinny (and often honky/nasal/ ugly mid-range sound). It's ironic that the argument for parallel is that you retain the pure sound of the guitar/amp, sure, with analog pedals, but these days most effects in the loop (delay/ modulation) will be digital. At least you have the option of a 100% wet (which amounts to a series loop); some idiotic amp manufactures still make amps with purely parallel loops and I'm getting tired of converting them.
