The charts shown are correct for o rings and quad rings. O ring “dash” numbers are equivalent between the two. Back up rings also follow this numbering system. The dash number indicates size. The prefix to the dash number determines material and form.
A great resource for o rings is McMaster Carr. You can find size, material, form on thier site, and the price for a typical bag of 50 rings is usually in the $7.00 range.
Sorry if this derails the topic, but I thought it could be of use.

"use it 'till it breaks, replace as needed"