I also fly electics, and I have found a pretty simple method to tune the thrust. First you need a better way to measure your current thrust. I bought a digital postal scale, and then made a trianglar bracket on a stand that will transfer horizontal force into a downward force. I simply tie the model to this with fishing line, apply the power and see how much thrust I get.

The next thing to measure is the amps, this is basically going to tell you how much flight time you are going to get at certain throttle settings, but more importantly it will tell you if you are going to burn out the esc or motor. Most will take surges over their ratings. It is not easy to find a cheap amp meter that will measure over 10 amps. (Mine only goes to 10)

Given this setup I then try a bunch of different props to tune the thrust verses the amps being pulled. Putting on a larger prop with more pitch is going to increase the thrust and amps but of course lower the flight time. If after this you are still not getting the thrust you want, increase the battery.

My rule of thumb for a plane that will do good arobatics is 1:1. Same thrust as weight. 3D you need 1.5 : 1.

Good Luck,
Larry