[r_u_f_u_s]

Owner and Co-Owner are pretty much the same position, with same rights, powers, and duties, however if you want to keep things maintained and run properly you should have a system set up. The system could either be that the Owner has slightly more power than the Co-Owner in organizing everything but not in running it, or that the Owner and Co-Owner have equal power but should verify everything important with each other. Look at it however you want, it's not a big deal ;-)