Neutron stars and distribution of heavy elements
I may do some more detailed calculation, but I think there is a misconception that has provoked your question.

The content of (e.g) gold, with respect to other elements in the solar system can be readily measured in meteorites. The Earth is expected to contain a similar abundance, but is very depleted in hydrogen and helium and somewhat depleted of lighter elements like carbon and sodium. The surface abundance of gold in the Earth is then a bit lower, because it sinks during the Earth's formation.

We expect the relative abundances of chemical elements to be quite smoothly distributed in space and time. Material that is produced in supernovae and neutron star collisions is mixed quite quickly in the interstellar medium. Thus the material that makes up the solar system is contaminated by the excreta of as many as a billion stars that lived and died before it's birth. Even if a neutron star merger occurred right next to the molecular cloud that formed the Sun, that cloud may have contained a million solar masses of gas, that would have diluted the signature of the kilonova event. We expect this to be true for all stars born in our Galaxy, except those that were born right near the beginning, where individual "pollution" events might become apparent.

The rate of these events in the local universe is only known observationally to an order of magnitude. In the past, it is also rather poorly known, but can be indirectly deduced from the rate of short Gamma ray bursts (of which we see only a small, uncertain fraction), if we assume that all sGRBs are merging neutron stars and that all merging neutron stars produce sGRBs. The rate in our Galaxy is extrapolated from the properties of the meagre number of identified double neutron stars and their orbital decay rates and is about 1 every 50,000 years (so about 200,000 over the lifetime of the Galaxy).

These rates require that about 0.0001 to 0.001 solar masses of very heavy elements is produced in each of these explosions to reproduce the solar system abundances. In the recent event, the amount of heavy elements in the ejecta appear to be in that range.