1. A blind man can pick a perfectly ripe tomato. The bottom of the tomato yields to gentle pressure with your thumb. Some heirloom varieties do not have the uniform ripening gene and as a result, even when completely ripe will have green shoulders on top. So judge by the bottom!
2/3. This depends on the variety, but there is a great pictoral timeline on TomatoSite.com. The site used to be TomatoEnthusiast.org but they let that name expire and never updated any links.
http://www.tomatosite.com/index.php?...Truss_Timeline