IMO the 26's are superior to the 52s unless you have a deep tank, like 30". According to AI 2 26s are more powerful than 1 52, I think because they cool better, but the real reason I went with 26s is because it splits the pucks. It's only slightly more expensive to run 2 26s over 1 52. Shading is a real issue, as is coverage with LEDs in general. IMO if you have a proper number of LED fixtures there should be no hotspots really, just an even PAR number across the the tank at the fixed depth. Breaking those 4 pucks in half increases power and distribution as you can position them wherever you want.
I just used the AI classic rail kit with the hanging attachment. You can see in the pic that I used the spacer for the 52s and mounted the lights parallel instead of perpendicular for the 120's depth. Also with the director you can run the fixtures at different times and intensities for different coral - another advantage of having more 26s over less 52s. Unless as I said the tank is deep and you need the power of those 4 pucks. The spread pucks is also why I like AI right now over radions.
I have a simple lighting schedule. 1hr ramp up - RB, DB, V UV at 95%, W, R G at 45% for 7hr before ramp down over 1hr.
Hart, beautiful work ! i'm running 1 hydra 26 over a 40g IM which i'm already seeing i'd rather have two to spread the lighting out. You mentioned your lighting intensity, now sure how long you are running your lights for also if you can share how high about the water surface would be wonderful! Thanks!