Currently, we only support the upload of .gpx, .itn, .mpjs, and .kurviger files.
The reduction is only applied for routing, not for displaying the overlay. Currently we support no more than 200 waypoints, but I recommend to stay below 50, since adding more points might negatively impact your experience. A guide about import GPX Tracks can be found here. If your route contains less waypoints than specified nothing will be removed.