Getting down to the science of it.....
Rain-x works as a hydrophobic coating..... it deposits a layer onto the glass that will repel water, to cause it to bead up so that the water will easily roll off of the glass.
In contrast, water on a perfectly clean glass surface will not bead up but will 'sheet' across it... a thin layer of water with no breaks.
If my understanding of silicon for rubber is correct, it's more of a surface treatment to act as a lubricant or a preservative layer to help prevent oxidation of the rubber.
It appears we are looking at two different treatments here..... one (silicones) to protect and lubricate the rubber wiper, the other is a hydrophobic coating for the glass surface.
My experience is based on my engineering position in the optics industry, more specifically, optical coatings on glass and plastics used in the avionics, medical, military, and other high-end optic displays. We routinely deposit hydrophobic coatings for the additional environmental protection they provide. Application consists of vaporizing the coatings in a vacuum chamber which deposits a layer onto the glass product. We do not deal with wipe-on treatments.
For glass cleaning, I read years ago that one of the major wiper manufacturers used Bon-Ami to clean their windshields to test their wipers. While Bon-Ami can be considered an abrasive, so can cerium oxide, which is considered a 'polish' for glass.
I'll encourage you to do additional research on what I've mentioned.... just trying to lead you in the right direction.