Was 8-6-6 because a couple different brands?
Are you considering 8-11-6? How about 8-8-9, or are the angles wrong?
I wanted to way over-panel (like 50% over), putting two strings into each input. Each string of two orientations, bringing peak current back down to what it could handle.
I use 8, SunPower 327W panels per string, which stays under 600V. That's about 2500W STC.
With the 6000US and 8000US I got I can do pretty well with that, using 4 strings of two orientations. The 5000US, doesn't seem such a great fit; for now just have two strings.