JHorr,
I have a Beneteau 311 with a traveler similar to yours. My boat has the standard keel, not shallow draft, with 4' 8" of draft. I find going upwind I need to reef at 12-14 kn true, otherwise the heeling and leeway are too great. Flattening the sail reduces heeling a great deal, although an older Dacron main will be limited in its ability to flatten. In some local races, crewed or singlehanded, I find I start making a huge amount of leeway if my boat heels more than 15 degrees. With a boat behind me on the same heading, I can see that I drop 50-100 yards to leeward in just 5-10 minutes, especially in waves. It can be quite startling. If I'm heeling 20 degrees or more, then the weather helm really picks up and the boat will eventually want to round up. So I reef the main even in races as soon as the heel is consistently above 14 degrees, and if it's marginal I work the traveler up and down. My speed usually holds up and VMG is usually the same or better. My traveler is also at the front of the companionway. Reefing the main before the jib will reduce the tendency to round up, and my boat seems more balanced that way. The jib and main are similar sizes on a B311.