the compressor will sound much better on the signal POST preamp, rather then after a guitar. It's just its character. This is also true for analog compressors. A DBX sounds great after a pream, whereas a Boss or TC footstomp are great after the guitar.
An H8000 fof a dsp running only a compressor is definitely overkill.
On the 7600 you should use MIDI Virtual racks as they are and connect the Eventide AFTER the preamp, not after the guitar, using XLR cables. Forget about routing things thru the Switchblade as it's not the case here.
Gtr > Preamp > H7600 > Power Amp