One of my bikes has the matte or stain black paint. I have never used anything on it but soap a water. Seen to many get messed up. From what some have reported the F11 Top coat works well to protect it. I have not tried it yet.
As for S100 Corrosion protectant is has never cause an issue on anything. Works even on seat. I do ride in winter. My Fb is 22 years old still looks darn good , with the side car it has logged a few miles in snow.

 

The last day I rode in to work there was snow forecast for that evening so the State of Delaware decided to spray the roads with Magnesium Chloride brine. The road that the industrial park I work in empties into was coated with wet brine when I left work. A few days ago I noticed a puddle of water under my bike in the middle of the garage. The brine that got on the bike was absorbing water from the air so much that it was dripping off and puddling under the bike. The forecast Saturday is for temps in the low 50s so hopefully I can get the bike on the ATV lift out in the driveway and pressure wash it off.

 

I too, know a few guys and gals in NW Ohio that use a pump spray bottle with 1 part white vinegar and 5 parts water to hose down the bike and rinse with water. On the road I would suggust going to a dollar store, but a $1 spray bottle, and a small bottle of white vinegar, go to the car wash and spray down the bike with the spray bottle and then use the spot free rinse selection of the wand to rinse with filtered, low pressure water.