Auralic Altair into Luxman L-450 settings?

Gain structure is a mystery to me and I'd be grateful for any advice. I just hooked up my new Altair to my old Luxman L-450 and I am wondering: What are the optimal connections and settings? Right now I'm running the Altair output (streaming Roon) to the aux input and I have the Luxman volume knob set at about 10 o'clock, with the Altair at about 30 for regular listening. Should the Luxman go even higher and the Altair lower, or the other way around? I've tried both ways but the A B testing is hard. Also: What about the tape in or the "signal processing" in? (This is mostly for low volume listening.) Grateful for any advice!
I would disable the Altairs volume and just use the Luxman. It will sound better that way. You can use the tape input if you like or the aux or tuner inputs they will all work. Do not use the signal processing or phono inputs.
Thanks Jond! The problem is, I want to use the volume control in the Altair, which I can control via Roon. It sounds like I should try to keep it as close to ax as possible though, like normal listening at 85 or 90.
Luke yes the Altair will sound best with its volume as close to max as you can get it.