Ai ext bracket question

[chrisl10]

I am in the process of building my dsa 105 rimless. It measures 48x24x18. I just purchased the AI ext 48" mounting brackets and the 6" top extender bracket where the lights mount to. My question is is the 6 inch bracket enough or is the 12" what I need to center it. The bracket is mounted behind the tank so it comes from back to front. I don't have the lights yet and probably won't till after Christmas and the holidays(3 kids) $$$$$ lol anyone that has the AI hydra 52 with any thoughts on this?

 

[FLSharkvictim]

I would recommend going with the 12'' ext Rail! Here is my set up and I used the 18'' exts for my 120 and here is a shot and my current settings.
White: 50%
Red: 10%
Green: 10%
Blue: 75%
Royal Blue: 75%
Violet: 10%
UV: 10%

Tank info:

120 Mixed Reef
Ecotech M1 pump
Skimz 163 DC Montzer Series skimmer
Custom sump / Refuge
2 Maxspect Gyre XF130's Pumps
2 AI Hydra TwentySix HD LED Fixtures
Celestial C35W Maxspect Grow Spot light
Aqua UV Ultraviolet Sterilizer 25w
BRS Dual Media reactor
Eshoops IV Master doser
Tunze 3155 Auto Top Off