1986 Toro 824 (Tec 8HP L-head snowking)
I don't blow any snow until it's off choke and the exhaust gases feel "hot". It also warms up faster the sooner you get the choke off (leaner mixture - more heat). I start it as per procedure (apparently starting at full throttle is important to have high enough revs to splash oil around enough for proper lubrication - it's been suggested that starting at idle is actually worse for the machine). I lower it nearly right away to about half throttle - not idle, not racing and click the choke down each notch as soon as it'll stay running that way. I usually locate the edges of the driveway and clear the porch and get going. In warmer temps we have during most storms, this is probably less than one minute.
I always run the machine at "full" operating speed - the engine is meant to run there with proper lubrication and slowing it down gets you into a screwy place in the torque curve and just doesn't move as much snow as far. The only time I'm throttled back is when I'm between houses working on a walkway and it's deafening between the brick walls at full whack.
I blow EOD at the beginning of my run, after only one or two passes of the driveway and everything's warmed up. Why? Two reasons. EOD is full of salt here and I run the rest of the driveway's clean snow to get the salt out of the machine - less rust. Also, if the machine is going to break for some reason (remember, it is a 1986) I'd rather have the plow pile done. I typically end up blowing my EOD, clearing the gutter full of EOD over 100' down to the nearest storm drain, helping anywhere from 1-9 people with their EOD or whole driveway, doing my driveway, running the machine dry after fuel shutoff, sweeping it off, and putting it away. Fun fun.