You probably know this, but you don't necessarily need an HT bypass to make this work. You can just set a HT "reference" volume level with any preamp (I used 12:00 or halfway for simplicity's sake) and when you're listening to HT just turn the knob to that position and you're good to go. Not quite as elegant as an HT bypass, but then you're not limited and can choose from any preamp available.
Best of luck.
Best of luck.