I'm still very much a beginner, so calibrate my input accordingly! I'm interested to understand more about it all myself, so am as much asking for comment/clarification as I am making suggestions.
1. I have been taught that to determine ends per inch for a balanced weave, wrap for half an inch, use that as your ends per inch. (Allows room for the weft threads to go in and out.) Since you are wanting weft-facing, I am understanding that you need less ends per inch for the warp? (And presumeably beat harder?)
2. If you want more epi than your reed allows, you can double up ends in slots. Conversely, if your reed is finer, you can miss out slots. (Provided there's room for the yarn to travel through the slots, of course.)
Lesley is suggesting 6 epi with Aran weight, which I would think you would sley on your 8dpi reed 1-1-1-0-1-1-1-0, wouldn't you? I assume the warp threads will even themselves out as you beat and the weft finds itself places between the warps, so you wouldn't get gaps where the empty slots were.