Here's an idea - check the archives on this site.
This is the sort of thing you are going to find - tons of great information.Following is a posting from the archives on this topic - They're not jackstands...The stands for boats are "poppets", not "jackstands", which are for automobiles (I assume you're not using the automobile stands!). "Poppet" is old English for "puppet" or doll, which they resemble when they stand up. (A couple of the pirates in the film "Pirates of the Caribbean" called Keira Knightley's character "poppet" in the scene where they kidnap her).I assume the labels on your new poppets will have a capacity rating, which you could use to add up and decide whether you have enough. (It sounds like your 6+bow will be plenty, but their size will matter). I'm sure someone on the forum who works in a yard will tell you the details for getting best placement. Chains securely connecting the necks of the poppets to each other laterally underneath the hull are essential for safety.