I actually made my own prototype patrol shelter using a beak at either end before my Appalachian trail thru hike with the Patrol shelter.
I tested my prototype at the BPL Henry Coe get together last February.
The pictures are NOT from the BPL event! It was hailing and colder than heck there! I think Tony has some pictures on here of my tarp at the event.
The results of my test convinced me to get the Patrol and in cuben fiber rather than the sil-nylon of my prototype.
Here is a picture of my Prototype "Ray Way" or patrol shelter tarp..
I sewed this out of an 8'X10' MEC flat tarp.
I concluded that having a beak at both ends left too much exposure.
On my AT thru hike I found the patrol to have plenty of ventilation even when pitched close to the ground.
In fact i would sometimes use my GoLite chrome dome trekking umbrella under the beak of my patrol as a "door" to block excess wind or when the wind changed direction.
Usually i set up my Patrol with the closed foot end towards the prevailing wind.
Well back east they have horrendous weather.
You can be awakened anytime during the night by mic ro burst winds from humongous thunderstorms.
Maybe it's because i am a sissy west coast boy, but they really do seem to have unreal weather back there.
Having a "closed" end to my shaped tarp (Patrol shelter) meant i could always count on a defensible space.
My two beaked prototype was like a wind tunnel by comparison.
As for room inside, you must remember that my values for a long distance hike were: #1 weight, #2 ventilation/protection from elements, #3 ease of setup.
I was, and am, prepared to sacrifice volume inside my shelter becuase the shelter's primary use on a long distance hike is for sleeping.
My strategy is to hike, rain or shine, from sun up to sun down. When I am not hiking i am in my quilt, under the patrol sleeping.
This is entirely different from my strategy for a back country fishing trip or a winter snowshoe trip where i might be tent bound for longer periods.
I did find i had plenty of room to keep my pack and all extra gear well under the patrol with me each night. It's not like i could have done jumping jacks under there but for the hour or so before i drifted off to sleep i would munch tortillas and read guide book pages in relative comfort using my food bag as a pillow and propped up on my elbows.
I had enough room each morning to pack everything into my pack under the Patrol, eat breakfast and slip out into the rain putting the patrol away in the mesh pocket of my pack as i hiked away.
Being able to set up the Patrol in the driving rain, crawl underneath and unload my dry bivy and quilt and crawl in for the night was amazing.
One remarkable thing about the Patrol was how little condensation it accumulates.
Either the cuben fiber itself has some intrinsic property involved or the ventilation was superior to other shelters i have used.
Even under daily rain and high humidity, my Patrol never accumulated the same amount of moisture as other shelters i have used.
I have used a Choiunard Pyramid, Gossamer Gear One, Sierra Designs Divine Light, as well as a flat tarp/poncho for hikes before.
My two thru hikes previous to the AT I used the GG One.
I loved the GG One. However the only failures i suffered were from having the floor attached to the fly where either condesation or actual rain would pool in the bathtub floor and cause difficulty.
This is why i chose a system that had a seperate fly and floor for the AT.
As for the advantage of two beaks.. i suppose it gives you a second view.
I think separating the floor from the fly is a huge first step in the right direction (for me at least).