PI Roles for Production

We are implementing PI/XI and have now installed the production box for it. The consultant who is configuring the system is asking for access. Should I still give him the SAP standard roles for PI? Or should I create custom roles instead? I actually created the custom roles for the QA box but when I assigned it to the consultant, he couldn't logon into any of the web based tools (like SXMB_IFR). So I had to give him the standard SAP roles for PI. Is this how it should be? Does that mean I should also assign him the standard SAP roles in production?

Thanks in advance! Your responses are highly appreciated.