Type1106,
about the limitation you quoted that CAT I approaches with an RVR of 500 m are only possible if the airplane is equipped with a suitable auto-pilot (coupled with the ILS) or with an approved HUD and that without this equipment the RVR has to be at least 800 m.
Actually, that limitation is only applicable to single pilot commercial operations (see page 77).
For multi-pilot operation (or general aviation operation), the first limiting factor is the availability of a full approach light system (fully operational).
Luc