Search for superior drummer 3 percussion maps in the forum, there’s a thread where very high quality maps are shared for free. I could import midi tracks from SD3 directly into Dorico but *it requires that the percussion set is mapped correctly before you do that *. Otherwise, the data corresponding to each instrument has nowhere to go, since the instruments do not exist 
Jestermusician’s excellent percussion map for SD3
Use the template that comes with the maps.
Hope it helps.