How do I do this?

Im doing an experimental outdoor grow in a dense pine grove in 2010. I want to grow tall sativas (12 to 20ft pref) to get some sun over the density of this pine grove. So how would I go about making that curved funnelesque shape with a deer net? The idea it to make them grow tall fast and branch out filling the angled out area. Then taking down the net so it wont be as obvious and i can water/nute easier. We dont have any chopper flyovers either (might cut the size down by half anyway lol).

Tall strain suggestions are appreciated.

here is a pic of the edge of the grove its a good 3 square acres and denser as it goes in. (im probly off on the height estimation) But the pines get 2ft away from eachother in the place im planning on growing/clearing atm.