Allen: thanks for the tip. You should have seen my previous head position... I have lowered it quite a bit, but I do need to work on getting even more streamlined. I'll eagerly await any more pearls of wisdom.
Stud: I definitely surfaced too fast. Not just in my 100 start, but I came up too flat off of all of my walls. Maybe practicing in a 3-foot pool has something to do with that. I certainly didn't mean to criticize your pullouts -- a 5-stroke first lap is something I can aspire to. More underwater is definitely good. Especially off the start where I still have some oxygen. I probably just need to slow down a little off the start.
Glider: My last 50 was indeed painful, but not as bad as some that I have swum. I actually thought I had paced it well, until I saw my splits. Your splits were very well done. Speeding up on the last 50 gives me something to shoot for. I am definitely better the longer the race. You're right that I don't do a whole lot of speedwork. But I'm also not a fast-twitch kind of guy. Sprints are definitely my weak point, in every stroke.