According to your list you have 31 DA, 9+10+7+5=31. 3 units of 10. And yes bladestorm is more effective with a full squad. I understand about using only what you have, but you may have trouble getting anywhere on the board and I don't see the 1 wave serpent you are talking about in your list. You should also combine 2 units of SS into 1 and run Karandras with them, in fact infiltrate them as a forward position and do the same with the pathfinders. This will help stretch the board for you.
