The drains aren't going to be full siphon, so I would upsize them as you're going to have a mixture of air and water in the drains. I'm also not a fan of 90s, but your setup should be fine. On the return above the valve, I would remove one of those 90s and go from the elbow above the valve over to the elbow before the Tee. You may also want to look into using a 45 above the valve and then a 45 below the Tee if you have room to reduce one more 90. Remember, every 90 bend results in head loss and you have at least 6 per run for the return.
But those are just my suggestions.