If the conditions are not ideal you should not attempt a visual approach period. I am also against heads down manipulation of the MCDU while maneuvering low level. It is certainly nice to avoid landing on a motorway but hitting another aircraft in the circuit is no fun either. In answer to your specific question though if the flight plan is sequenced and the landing runway is inserted in the MCDU the donut is accurate enough to bring you onto the PAPI quite nicely. Once you are on finals follow the PAPI and you will have no problems.
By all means use all resources available, tune the ILS, extend the centerline, use the miles to go, the distance to the runway,etc but above all on a visual approach look outside. Autopilot on, pushing bottons heads down absolutely not the the way to go at 1500 AGL.