Fin and Nose Cone Section for 1" Compressed Air Rocket

I saw this kit in the latest MakerShed newsletter: http://makezine.com/projects/make-15/compressed-air-rocket/
Had to make one. I used this valve instead,
http://www.amazon.com/Orbit-57101-Sprinkler-System-1-Inch/dp/B00004S1V3
which is 1" versus the 3/4" valve in the kit. I figured bigger port means faster rocket (I'm not an engineer though).

BTW, this launcher is pretty cool. We got over 100 yards on our first shot! The above rocket lasted two flights. The paper tube crumpled on t