I want to weave a weft-faced double width rug on a 4-shaft Leclerc loom. I don't know how to combine the fact that for weft-face I need to space out my warp threads, while for double width I need to double the epi. For the warp I chose a thin cotton which shows ten wraps per one inch on a ruler. I need to double that for double width, but then I need to have fewer threads in order to achieve a weft-faced weave. My weft is thick wool rug yarn I bought in a Bedouin village. Could anyone please advise me on the correct calculations?