Thanks for the update. I'll be interested in your results of height adjustment, as well as rake angle. My eyes and ears are at the same height as the tweeter on my D38's (by chance, not planned), but I haven't played with rake angle.
There are many theories on why a system can sound so different from day to day, but for me I think it's the varying sound quality and type of music that I listen to from day to day. However, I recently bought some SHM-CD's and have been listening to them exclusively for the last two weeks. System sounded perhaps better than ever last week and early this week, yet the last couple of days not so good. Strange, same exact recordings. I wonder if some of it is due to us personally - being tired, noise exposure during the day, or road noise on cummute home, etc. Some people think that power quality changes from day to day, and time of day; not sure about that one.
Take note of what you're listening to when your system is sounding good or bad, and see if your music is one of the variables.