Nice, crisp design. Personally, I think if you plan to go full-on-ink, leave your back as open as possible. In fact, even if you don't think you'll be filling your back, don't do it. Ink becomes an addiction after your first one, as you already well know. Save your back for something "big and special" as I lack better words to define it.
This started as the simple red "design" with the eyes, and has grown from there-
It's not a great photo and was taken within a few hours of adding the scape to it. I also have lettering on my back (yes, it's Latin, and no, it doesn't say "only god can judge me") which was planned to be worked into my final back piece. The overall point I'm trying to make is to have a plan, even if you don't stick exclusively to it. Just my 2 cents, good luck and I hope you enjoy your new tat.
PS: Lesson learned on my end, take into account your body size- as you can see, my first design (in red) was actually too small for my arm even though it spans 5" across and almost 7" vertically. On a side note, that "addition" (with smoke breaks by me and my artist) took 5 hrs.
