Hi Chris,
In answer to your "power to weight ratio" dilemma, you can find some very informative information at the HEADSUPHOBBY.COM website. Here's the path:
Go to the HEADSUPHOBBY.COM website, then click on "Help & Information Pages", in the upper menu bar.
On the page that follows, click on the "Brushless Motor FAQ" button.
Topic #3 gives a very understandable explanation of "thrust to weight ratio".
I personally like this site when it comes to shopping for brushless motors, because they provide very helpful data ( in chart form ), concerning "Battery Size", "Propeller Size", "Thrust", and "Amps", for many, if not all, of the brushless motors they offer.
All of this info can be very helpful in choosing the right combo for your bird ... provided that you have a pretty good idea as to how heavy your finished masterpiece will be.

Hope this helps.