Typical pointing errors during a single-dish observing session at 1.3 cm, with the DSS63 antenna are lower than 10", but a good pointing model may degrade after several months.
We advise to perform pointing checks at least every two hours, using a calibrator with estimated flux density higher than 1 Jy. We have been succesful using sources with about 0.2 Jy with good weather, but it is better to be conservative in choosing calibrators, since the flux of these sources can be highly variable.
A good reference to select pointing calibrators is the VLA calibrator manual:
You can use our Point Sources Search to search differents sources by bands, flux, sources names...