I'm pretty much with bowhunter. Upper 40's this morning; started with full choke, backed off to ~1/2 or 2/3 closed within 1/2 minute or so, took off and was full open by the time I hit the end of my development, say a mile. Probably a little quick, but then it was a striaght run at 40 mph for a while right after.
5 minutes of full choke would, well, choke it to death.