For draw length I prefer to look at rear elbow position. I believe this is the best indicator of draw length personally. From a side view I like to see a rear elbow that is at least level or slightly higher than therelease wrist and bow hand, and from behind I like to see a rear elbow that ishorizontally levelor slightly outside (right) of the and release wrist and bow hand (assuming right handed shooter)For hunting purposes higher and/or outside can bebetter to allow you have enough range of motion to stay behind it when shooting at odd angles or from less than ideal footing. For target, I personally do best shooting a bow that has me almost level both horizontally and vertically at full draw with that rear elbow.

I really couldn't care less about nock position to be honest, that has little to do with the overall geometry of your form as a shooter. String position can also beon the tip of the nose with nearly any ATA length of bow by tweaking loop length for most average draw length shooters. Make the true draw of the bow (string to throat of grip @ full draw) shorter, and increase loop length for a longer ATA bow, or for a shorter ATA bow make true draw longer and shorten the loop. You can accomodate most any bow out there tojust touch the nose onpeople under 30" draw length or so most of the time this way. My personal opinion is that if you can't get your nose on the string by tweaking loop length, you are probably too long of a DL for that short of a bow. At over 30" of draw length, I can get my nose on the string with a 32" bow pretty easily by extending true draw and using a short loop, but not everyone could do this.

Here is a quick video of me that shows my rear elbow position on a target bow at full draw. My hunting rig will be 1/2" shorter and will have that rear elbow a bit higher to help me stay behind it when shooting with bad footing or odd angles.

http://smg.photobucket.com/albums/v283/ringostar40/Archery%20Competition%20and%20Form%20Pics/?action=view¤t=24958d05.flv