I should point out that I don't win any races where I wear the cam.

However, unless you're a pro or there is a two man leadout train in front of you going 40-42 mph, at 450 meters to go 3rd position is way too exposed. With a headwind, doubly so.

Just looking at the bare statistics (excellent position in last turn, not excellent finishes), it seems to me that you're trying too hard to get good position. If you burn half/all your sprint getting to third spot, you're going to explode just when everyone else is getting going. I'll sacrifice position for reserves with as little as half a lap to go (600-800 meters to go) in order to save something for the upcoming sprint. I want to start my sprint in a relatively fresh state, not from an aerobic redline.

When there is a stiff headwind I try and jump from 3-10 back at 50-150 meters to go (depends on how fast the sprint is and if there's a hill). Faster = further back in field, longer jump. Hill = further up in field, shorter jump. I think my sprinting time is about the same, but going 30 up a hill is way different from 40 on a flat, or whatever it may be.

450 meters to go is half a lap in many crits, and I'd think that at that time you'd want to be 10th-15th spot if it wasn't single file, driven by super fanatical leadout trains, and going ballistic (otherwise you'd want to be just about 10th, maybe inside that by a spot or two). 20th would be good, if you can move up before 200 to go without killing yourself.

One of my better helmet cam races is the 2007 Nutmeg state games. I didn't realize how far back I was until I edited the video and counted heads. I think at the bell (1 mile lap, 1.6 km) I was about 30th. Halfway around the course I was still about 25th, so that's about 800 meters to go. I moved up pretty aggressively at about 500 meters to go, settling into top 10 just before the sprint. A crash put me into soft sand, but I was feeling good and I was anxious to do a big strong jump. Oh well.

clip:
http://www.youtube.com/watch?v=h-gqK3VKNqs

cdr