Reporting in, after setting up the stuff that's arrived over the past week.
I now have a Minidsp SHD as a pre, going into an Audiophonics ncore 250 stereo module via balanced. Also set up a usb-to-trigger between them and it works flawlessly. Other sources going into the SHD are: chromecast audio (toslink), android tv / video (rca for now - could't get the ARC to work and get a spdif out of it, yet), phono into ifi zen phono pre, then balanced pentacon out (xlr). Ncore is driving a pair of Harbeth P3ESR booshelfs on stands. Sub is still missing, as I'm waiting on either kc62 or svs microsub 3000, whichever arrives first.
First of all, my worries about pre signal being too hot are gone. It's just perfect this way and I get a nice range of approx -70 to -15.
Second, this sounds so clean! I've been toying with the idea of putting a Schiit Freya+ before the ncore as a way to play with fuzzing it up a bit, will probably try it out. The sound now is as transparent as you'd wish for. My A-S500 was a bloated distorting mess compared to this, judging by ear.
Third, the iFi zen phono pre... It's the first thing I hooked up, before I got the ncore and I had the SHD going into yamaha. When I played a record, I kept checking if it's not a digital source playing, it sounded that clean and straight. This will definitely improve my vinyl experience immensely!
Now I'm going to play more with DIRAC, I've done a few rounds and I'm getting better and better results. The 50Hz room mode is easily taken care of, but now I'll try to customize my curve to tailor it better to the Harbeths. I think the default flat curve is making them a bit thin, but I got a lot to play with now.
By the way, the entire switchup, complete with reprogramming the harmony took me just a day. I made the 4 cables last night, then today I managed to pull the cabinet apart, install and wire everything up and tidy it all back up. I lost like 2 hours trying to hook up the TV digitally. Even did a new dirac setup, all of that alone with a sick 3-yo kid jumping on my head, trying to engage him fully in the project.
Now my SO came home and just turned on the news on TV with the remote. Nothing has changed for her, except she gets much better sound and better control over volume