O.K. I have never used these ballistic calculators on the internet for drop because I spent a few $$$ to go to a school to learn this stuff. ( 2 days in class room and 2 days on range with personal insturctor) I will be attending another class in March 2010 for more advanced instruction. With that being said; Welcome to the world of long range shooting. I kinda' know your going to go to 1000 yards. I use a chronograph to determine my muzzel velocity on my ammo and I use a Kestral 4500np to determine the weather specs I need to calculate. I did look at the Hornady ballistic calculator however after reading your post. Several things you need to put into these factroy ballistic calcualtors or to figure to do the math yourself are as follows. Aside from caliber you need to know the ballistic coefficient for the bullet, the grain weight of the bullet your using, the muzzel velocity in fps of the bullet, the temperature, the barrometric pressure, your true sight height, the wind speed, and your zero range which you should have a zero at 100 but your zero is O.K. at 200 with this calculator. One thing not asked on the calculator is relative humidity which makes a diference in drop as well. Also 1 minute of angle adjustment in a 1/4 MOA scope is 4 clicks. Description in this Hornady calculator which I assume would require brand of ammo and factory named type, bullet weight in grains, and bullet type I belive will auto fill in some of the other "boxes" in this calculator which should make it somewhat easier on particullary the muzzel velocity.
All this info is critical to calculate your external ballistics and to have these calculations somewhat accurate.
As far as in field real time weather info device look up the Kestral 4500np thats what I use and it works well. Also It's kind of a cool device to have when in the "outback" on longer term camping trips. Also, instead of keeping my data written on paper notes, I use a ASUS heavy duty PDA loaded with the ballistic software I need to keep my info.