I had some time free up. I was listening to the amp in the background most of morning. I also did some quick and dirty measurements. I am still learning how to measure properly, and this was far from ideal. Mainly, I wanted to make sure that it was at the very least built without any major flaw that would show up in measurements, but not through listening.
tl;dr - it all seems just fine to me on both accounts.
Quick Power vs. THD - Both channels behave identically and to expectations for all practical purposes.
Representative channel at 1W 4R and 1W 8R - channels behave the same for all practical purposes.
PSU is clean enough. It's not to the extremes of my "wretched excess" external PSU, but it's quite good and about 1/10th the weight... and it's in the same chassis.
15W 8R and 25W 4R - Practical / Rounded power output limits.
Clipping behavior into 8R - Nice and even. I could have sworn I did 4R also... but I may have forgotten to save the graph.
Noise and A-weighted noise. Looks a mess, but it's all below ~95dBV. What really matters is that it's dead quiet...
What I built this amp for and what it definitely excels at is low-level listening. However, what I also wanted was a "bullet-proof" system for when kids come over and want to turn it up to "11". With an Iron Pre at 6dB of gain + the 12dB of gain with the amp, it can be safely turned ALL the way up. It plays to pleasant if not loud volumes without sounding strained at all.
More to come, but lovely, lovely amplifier.
If anyone sees anything of concern, let me know, but for now... it's just getting settled into the system.