Ya, I hear you I'm in the same situation myself.

if you spread them out 1-2' from each other you can get what is called the 3rd-light effect (the overlapping light rays cover what would take 3 lights to cover)
Sounds good bro. Good call on the RO as well, that be too much water to buy and haul in.
For sure it will, I'm assuming your on city water? I got lucky with my supply from my well, 8 ppm. Have to supplement it with calmag. While on that subject, before adding anything to your res calmag needs to be first. I'll bring my water up between 125-150 first thing with the CalMag.