Distance between hanging Rings?

I found someone who can beef up my ceiling joists so I can hang my new rings. I am going to have him install eye bolts so I can hang the straps. What is the recommended distance between the eye bolts?

My ceilings are only 8' tall but it will still be much better than my current setup where they hang from a door frame mounted chin up bar.

thanks.

For individual set ups....Your shoulder width is common.
"FIG"(Federation of International Gymnastics) standard is 50cm or a little over 19inches.

Hi Ted, 50 cm it is the correct distance.

Thank you both for the info. Much appreciated!