Have you completed the change and setup to improve soundstage? How is it sounding? I have previously gone a similar route to your system, with a 3 channel stereo setup. I find the flexibility to alter the soundstage to be a bonus depending on speaker spacing, overall placement allowed by room as well as the degree of toe in. Amps currently in use are Rotel RB 1572, Rotel RB 1590 and my reliable Acurus A250, Preamp custom rebuilt Superphon CD MAXX controller with sepearte power supply, Audioquest cables. 2 PA 505 subs. Have not got these placed right yet. Speakers B&W 804s (Cherry), upgraded Rtia7's (crossovers, 3 Russian teflon capacitors, .22 uF in parallel one for tweeter, one for mid and one for woofers. Last pair of speakers Monitor 70 series 2 with upgraded crossovers as well.
This is a fantastic setup!!! Wow. Have not got mine up yet, but like your setup the variety and configuration complexity is there. I am waiting for one more Amplifier to arrive and connect. What do you enjoy the most about your setup with regard to Listening to music. Appreciate your schematic!