Advance spring
If it pings under light load, & you are using VA, you have two options: delay the centri curve with heavier spring &/or weights......or adj the VA rate. [ Allen Key adjustment ]. If using manifold sourced VA [ smart people are ], you need to make sure AFTER using the AK that you still have the same timing at idle....& it is steady.
If the ign system has been dialled in already, & everything is working ok but just getting some light throttle ping, it is better to work on the centri curve to fix the problem. Heavier springs or lighten the weight.