Well, what is ideal is if you get native wild bacteria, mostly local b. linens. to grow on the rind.
You want nothing that will bloom at all -no fungus (mold), no yeast. Nothing that will give you any visual evidence of its existence other than color change.
I am not familiar with all of the ripeners, but all that is permitted by law for most Alpine Swiss cheeses (the actual Swiss ones, not imitations) is b. linens, and then generally it is preferred by most makers to add nothing.
When cultured b. linens are used for cheeses, they don't add them to the milk. Instead, they rub them onto the finished cheeses.
The basic rule of thumb is that if you see anything grow during the first few months at all -we're talking blooms or yeasts here- you wash it off. It might take some time and practice and you may have to experiment to find what wash mix works best for you. But again, the idea is to get a cheese surface that can dry off without cracking and that will not harbor mold. It may be that a few spots of blue appear here and there while the cheese dries off -just remove them before they amount to anything. But you should be able to let the cheese dry when a good washed rind is developed.
And to help understand the science here a little,
A washed rind in not a sterile environment free from any culturing agent. It is not slat treated and preserved so that it can dry out and stay plain cheese without cracking. After washing, the rind is chemically totally different than the cheese inside, and this is why it protects and preserves the insides of your cheese.
Bacteria grow on the surface of the cheese, consuming fats, proteins, and sugars and releasing certain by products (this is the basis of the 'Schmier'. This will first be a somewhat thin paste, more like dirty wash brine. Over time, it gets thicker and pastier as the bacteria dissolves more of the surface and turns it into paste. In theory, once the smear is well formed all you need to do is rub it down with dry salt, but I usually keep washing it with the brine to add flavors. As the paste dries out, it gets like a wax that can easily rub off of the cheese when you handle it. Wetting this waxy coating will turn it back into a thick paste. This will eventually dry out too after a period of months, forming a hard shell. The hard shell should get somewhat slick when wet, but not easily transform back into paste. The rind, of course, is edible. In general, the form-side (don't know what you call this in English? We say Järbseite, or the side that is against the form) of the rind will be harder than the top or bottom, and on an old cheese may not be as pleasant to eat.
It is important that no yeast or molds grow for any period of time. These too, will cause chemical changes and release their byproducts, resulting in off flavors. The combination of a washed rind flavor and a mold infection is, in my experience, quite unpleasant and you often have to discard the rind. You can generally tell right away from looking if a rind has had mold or yeast infection that were not immediately taken care of. They will have dark spots where the mold was, or other spots or stands of off-color. (In my experience with a washed rind allowed to mold, you first get wild blues, which grow and stain the rind and are then overtaken by wild whites)