There are a few houses in our development that have used these. I'm not a fan personally. Strung in a row, the lights look like an airport runway. (The homes near me that have them also tend to have other things like poorly installed brick edgers and lawn ornaments from Lowe's in the yards and the result is Clutter.)

No reason to suppose the OP will install these in a row.

Nice backyard. You might look at all the options available for mounting. Some attached to the fence would offer nice downlighting.

Let us know what you find!
Rosie

dsb22...so what does your backyard or front look like then?

Posting those photos was a good idea.
It gave me an idea of what you have to work with and the elements that you have in your yard.
As I understand it, you want to 'bright up the back yard'.
My question is why ?
Normally when I prepare lighting plans for homeowners that have a hot tub in their back yard the preferred look and feel is for privacy, not high lighting.

The only lighting that is usually specified is for level changes ( at the steps ) and for perimeter mood lighting and accent lighting, example : on a large specimen tree or sculpture.

I didn't see any trees of substantial size but did notice a bird bath, which could use an up light with a very low watt lamp.
Your hedge could probably take a grazing light, ( an up light placed close to its subject for dramatic shadowing ) but to tell you the truth, I think it is a bit unnecessary.
From the look of it, there really doesn't seem to be much in the way to accent out in the softscape and from a practical privacy point of view , one wouldn't usually want to high light a hot tub area.

Most all low 12 volt systems that are 'hooked together like Christmas lights' will will have a 12 gauge wire that for safety's sake, should be slightly buried under ground. It's no more work than planting a relatively small plant in the ground and it will be safer than having loose wire on top of the ground.