I have crossed the Straight of Georgia in sailboats as small as 18' as well as larger. In daylight as well as at night. Watch your weather and if an experienced friend is along all the better. As Faster posted start with a reef if you expect rough weather. You can always shake it out if the breeze doesn't live up to the forecast.
While it isn't a direct help to crossing the Straight here's an interesting link.BigWaveDave - Windsurfing, Kiteboarding, marine weather, Victoria, Vancouver Island, coastal British Columbia, BC, Canada, windsurf, kiteboard, webcams, surfing, photos, kayaking
Click on webcams at the top of the page for current conditions in many places along Vancouver Island. A neighbor uses this site a lot, except he hopes for calm conditions as he is an avid fisherman.