Don't do it. You need every bit of expertise at this point.
Save your credits, and wait until you have WH. I'd also caution you against min-maxing until you have your full WH set (or at least done the math on what the full WH set will look like).
Waste of time. BM already gives you set bonus, so buy the 1 WH piece that provides the BiS MOD/ENH over and over again because you will be gaining BiS mods & 10EXP per piece in very short order.