I haven’t noticed this day to day variation he speaks of - personally I don’t believe that and just think that often we listen to our system in different moods from day to day and that has an impact on how much we enjoy it in that moment.
I found the signature to be quite consistent from the get go. I would say that they are on the warmer side of neutral, that they have a little recessing on the brilliance region but that can well be very useful. They have an almost golden glow to them in some ways. I have used them in both interconnects, speaker cables, and I even made a usb cable with their solid core conductors around 5 years back for my Lampi GG.
They didn’t take long to bed into my system tbh. In terms of their overall quality - I think they will help many systems that are more spotly lit or need a helping hand with sounding a little more tonally full - that is if your system is a little dry or analytical they could well help you get some balance if you don’t solve it elsewhere. In absolute terms versus audiophile cables and using audiophile terminology, they don’t have the black backgrounds / quietest noise floor of the “best” nor do they have the bass depth, power or texture of the “best” nor do they have absolute extension in air of the treble of the “best” but they do have an ability to make things more palatable. If your system is tip top balanced beautifully everywhere my gut says they will hold you back in absolute terms but for 95% of audiophiles living the “struggle” they will likely be worthy tonic. If you are an audiophile wanting audiophile type sounds then these are definitely not for you. If you just want to listen to music and not worry, they are worth a punt.
Imho ymmv etc