Great project, trying to make my own based on yours. But receiver is too damn hard to solder, those resistors arrays are driving me crazy. Did you considered ditching reciever and adapting bluetosis firmware? (:

Resistance arrays are actually easy to solder. All you need is an ordinary soldering iron and a good flux. You need a high quality flux instead of a normal rosin. Rosin may be useful, but the effect is not good.

Actually I am toying with the idea of designing an easier to solder receiver. I had the same problems with the resistor arrays but in the end I managed it using flux as @sunny said. I suggest you to give it a try.