Based on J. Hanson’s recommendation in his article my suggestion of a 2-ton floor jack is undergunned. I actually carry a 3-ton which, based on 2/3 of my 9200# GVW, is just about right. No thanks to any conscious calculation on my part, just happenstance.
Two reasons I carry the floor jack: 1) I already owned it, and 2) I witnessed a truck roll off a bottle jack. To be sure, adequate chocking and a functioning parking brake were absent. I like the features of the Safe Jack and if I were to buy something today, it would be a strong consideration.