Been There...
I went a couple of season ago. The tide was down and I had about6 feet of water on my meter. I draw 4'9" on my L37. It was about 4:00pm on a Sunday and everyone was heading home from the weekend. The channel is wide, but as Steve F said, follow the markers and you'll be OK. I came in thru Watch Hill passage and pointed to Stonington. The channel splits at the R/G marker and I followed the markers. Nice, relaxing place. Try the stuffed clams at Olympia's.