Hi Michael,
We were in Venice on a Saturday and Sunday in May, and it was crowded during the day but more in the San Marco Square area and Rialto Bridge. However when the cruises leave it is fine. And during the day we tried to just stroll through the streets so didn't notice all of the crowds.
In regards to the restaurant, I don't know about the one you saw in RS DVD. However there was a great Canal side restaurant that we ate at both nights and it is in Rick Steves book. It was called Trattoria da Giorgio ai Greci. They had wonderful food and it was on a quiet canal with beautiful views!
Have a great trip!