Drop-Stitch Tank: The Progress Made

I'm working on a larger project that's going to be a gift and I'm a bit stalled on the tank top. The drop-stitch tank is now at the point where I should be dividing the front and the back to start making the arm holes. This is the first time I've knit a garment in the round that wasn't a hat and I'm not sure if I want to just divide up the stitches or if there is more I should be doing. After working on this for so long, I don't want it to have an imperfect appearence. Also, out of the six balls of yarn I had, I'm now down to two. It seems unlikely to be enough so I order two more skeins but they're not of the same dyelot and now I'm going to have to stripe the yarn to blend them together.