Value of burn/break in?

Agree with the above answers. Leave the SS on 24/7 and if you work daytime hours then leave the tube preamp on in the evening and overnight.

I've used the Isotek disk to burn-in the entire system. It will speed up the break in time on the speakers.

have read that pretty much everyone puts their speakers toed in at about 45 degrees so there is a triangle listening arrangement

Toe-in depends on many factors. 45 degrees is common if you’re sitting close in the near-field. Different speaker designs and room acoustics will dictate the angle of toe-in.
My setup is in an equilateral triangle, but due to the dispersion from my speakers they are firing almost straight ahead. This is what the designer John Devore recommends and the soundstage and image are right on the money.
There are different theories on how to set up speakers, but whichever method you use, it’s always time consuming. Taking measurements, listening, adjusting position, then listening again. And each time you adjust the speakers it should be in small increments as stated above. One inch may get you to that perfect soundstage.

It should be mentioned that the rake angle of the speakers will play an important role in setting your desired sonics and image.

I dont think anybody has mentioned the acoustics of the room. Speaker placement and angle can only get you so far. The room needs to be tuned which involves using absorbion and diffusion.
If the speakers present a boomy or loose sounding low-end then bass traps are probably needed. Plugging a speaker port may help, but it will also affect the sonics, IOW you won’t get the full dynamics or best timbre from the speaker.
If the room is too lively, the issue of brightness may not stem from the speakers, but may be due to room reflections causing standing waves. This would be dealt with using absorbion panels in the key areas of reflection.

A setup disk can be very useful in determining speaker placement, but tuning the room will improve the overall sonics, improve clarity, and help reproduce the music as it was originally recorded.