B2B, commercial use (we want to provide this app as part of our product)
My question is:
Does this usecase fall into the “heavy use” paragraph of the tiles policy despite the small user size? If yes, which information does the [Operations Working Group] require to grant a possible permission?
imho you are asking the wrong question. A service run on donations and by volunteers (e.g. the tiles provided by the OSMF) isn’t well suited to serve a business use case. That’s why the tile usage policy explicitly writes: " OpenStreetMap data is free for everyone to use. Our tile servers are not."
You may receive a block or missing service anytime without having a partner to solve this. Don’t get we wrong, the OWG and the volunteering SysAdmins are doing a great job in providing the map tiles, but if they e.g. have to introduce new blocking patterns (which happened recently again), a lot of services that “hardcoded” the OSMF tile endpoints in their applications got blank maps.
So I highly recommend to use a commercial tile provider for any business use case - where you get support and reliable services for your mapping needs.
The policy doesn’t spell this out explicitly but the OWG doesn’t grant permissions at all. If your usage exceeds whatever at the current time is considered to be too much you will be blocked. So as @Spiekerooger points out you should not rely on the OSMF services for a commercial or otherwise end user application.