This is not my field of study, so I do not Know if I will be any help.
Without a true understanding of what you are asking I may be off base with this reply.
Gold in solution as clusters of atoms can have many shapes and sizes, as colloids these clusters will reflect light, the color of the light reflected is a different color for different sizes of these particles.
These colloidal clusters of reduced gold atoms can have many shapes and sizes depending on how they grow (they also grow by clashing and bonding randomly and their growth is thus random in size and shape).
Although when we precipitate gold and the two solutions are mixed the reaction is just about instant, and billions of gold ions are gaining their missing electron at the same time, and the process begins of forming clusters into the crystal precipitant, so the size range of these cluster of atoms, in a certain stage of the process would be close to the same (the clusters would be different shapes a of slightly different sizes) but with billions of them on a race to grow, they come close to being a similar size in that particular stage.
The colloids can grow in size as the atoms of gold collide randomly in solution, and bond together by their contact with each other, these clusters also clash together to form larger colloidal gold clusters, and can continue to grow until they become a crystal visible to our eyes and then be pulled down by gravity into a precipitated elemental gold powder we can melt back to the gold metal.
A colloid of gold can continue to grow, and can grow to form a crystal large enough to be seen and precipitate to the bottom of the vessel by gravity, unless something stops its growth in the process (stunts the colloidal gold particles growth).
As we see with the use of stannous chloride when we test for gold in our solutions, here the tin chloride solution mixed with our gold chloride solution, not only reduces the gold in solution, giving gold ions back those missing electrons, reducing the gold ion to a metallic gold atom, forming gold atoms free roam around and randomly clash together, and then bonding and combining into clusters of gold atoms, forming clusters of colloidal gold particles, and these cluster colliding together to form larger clusters up to a point where the growth is stunted (before it grows to a crystal to precipitate), the stannous chloride stunting the growth of the colloids at a certain size (range) of colloidal gold size( at a certain stage of growth), then forming a polarized shell on these cluster (of a charged anion or cations), which attached to the outer shell of the colloidal particles to keep them in solution, by the motion of them repelling each other, keeping them from coming into contact with each other, to grow into larger clusters or larger colloidal particles. The stannous chloride test gives us a color of reflected light of these colloidal gold particles in motion in solution. This purple color referred to purple of Cassius is reflected because of the size of the colloids involved (if the colloidal size was different the color of the reflected light would give a different color to our sight).
So here this makes me believe the stannous chloride always produces a certain range of size of colloidal gold particles (stunts there growth at a certain stage of the process of growth).
Other solutions can be mixed to give different colors, or different size of gold colloids.
This leads me to believe it is these other ions in solution that determine at what stage a colloidal growth is halted or stunted by polarization of the colloid.
This growth of a colloidal gold particles can be stunted, as other ions of an electromagnetic charge attach themselves to the outer shell of these neutral colloidal gold clusters, halting the process of growth of these clusters, as these polarized ions which form this outer shell of the colloid, giving a charge to the colloidal gold cluster, causing this gold cluster to repel other gold clusters of the same polarized charge, so that they can no longer come into contact with each other to be able to clash together and bond into larger clusters, and the repelling action keeping these clusters constantly in motion repelling each other around in solution.
I believe it is what (cation or anion) the other ions (polarized) that are involved in solution,that can determine size or polarization of colloids at a certain stage of growth of the gold particles, (as we see stannous chloride gives us a certain size of colloidal solution) a different reducing agent with a solution of different anions and cations in the surrounding solution of these growing gold clusters of atoms can stunt the growth at a different stage, different ions that can attach themselves to the growing colloid gold cluster that can stop this growth, by polarization of the cluster, concentration of these gold atoms in solution and what these other ions are, as well as their concentration, that can somewhat determine at what stage of growth the colloidal growth of the colloids are stunted, different solutions can give different colors of colloidal gold, these reflected light colors can represent a certain range of size of the colloids involved.
So I think it kind of depends what else you have in solution with your gold, (anions and cations) that can determine when the colloidal cluster will stop its growth (at a certain stage of growth) and form a shell of charged ions, and begin to repel each other.
Or free of these other ions contaminating our gold solution can allow us to complete the process of precipitating our gold from solution
