Related to this topic: We have learned from bad experience that one must not "split" any part of a conversion to towing between 2 different FSDOs. The FAA does not always function as a unified agency and in our case the FSDO where the seller was located converted the certificate from "restricted - agriculture" to "restricted- glider/banner tow." BUT the FSDO where we (the buyer) were located refused the paperwork to install the tow hook. They actually claimed that the first FSDO acted improperly in converting the certificate. Essentially, one FAA office was claiming that another FAA office screwed up. It took me (a lawyer and then club president) 8 months to solve that problem. So, absent a really good reason, I think converting a certificate from Restricted to Standard is just asking for trouble.
ROY