BackPacker, you might like to look at the BGA guidance in “Safe Winch Launching” Feb 2010 edition and other stuff on:
British Gliding Association >> Safety >> Safe Winch Launching .
Note particularly: “Ensure that the transition from level flight at take off to the full climb (typically 35º) is controlled, progressive, and lasts at least 5 seconds.”
(The safety initiative of which this is part has succeeded in reducing UK winch launch accidents by a huge percentage.)
Chris N.