From china you can get PWM 12v dimmers that are incredibly efficient way to dim LED's. (I got these for less than $2 each, and will dim 8 amps)
I also have some single pole double throw switch's in decora plate style (made for projector screen up/down low voltage control)
80ohms, 500 ohms and 500 ohms are the key values (that took some trial and error)
when switch is in position 1, it shorts out the center leg and the leg with the 80 ohm resistor, effectively making it zero ohms from the center wire to the low wire.
that shuts off the light.
when switch is in position 2 (center all off) you effectively have 80 ohms and 1k on either side of the center wire, which is about 10% bright or so.
When switch is in position 3, it shorts out one of the 500 ohm resistors making it 80 ohm and 500 ohm on either side of center wire, which is about 30-40% range.
My offgrid dimmable 12v edison style bulbs don't dim linearly like a led string does with these dimmers. By the time you hit 30%, they look full bright, but are pulling less than rated power. (EDIT: I just rechecked, my edison bulbs say non-dimmable.... which is why they don't dim linearly like my led strings do.....)
SO, I have dim that is pulling 0.2 amps, (that appears 50% of rated brightness) and full bright that is pulling 0.6amps... Considering I am putting in 80ah of lifepo4 battery (that I could pull 80%, or 64ah) That means I have over 300hours of continuous lighting avail on a charge. Now obviously I will be pulling other stuff off of battery, but it's kinda a cool stat on how much lighting I could get from my little battery pack.
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though, you got some of the needed wiring done.. 
