The problem with double strand knitting is that it's too easy to catch only one strand and have, in effect, half a dropped stitch. I knit without looking at it (because I lip-read to hear) and I would never knit with a double strand. Be careful!
Try a swatch with different needle materials to make sure you are on gauge. Not all needles knit the same way with the same yarn. For me, Addi turbos(metal) are very slippery whereas Indian Lake Artisans hexagonal woods will grab the yarn because of the corners and the wood. So test what you've got to see which result you like best.