Drumline Sounds for Dorico 4

You don’t need to use the Keyswitch field in the percussion map. That is intended for use when you need to additionally play another note along with the specified note in the percussion map to trigger an extra sound, e.g. note 60 produces a simple snare hit, but if you also hold down note 48, note 60 will produce a snare hit with a different kind of stick.

The basic steps for setting up custom percussion mappings are outlined here:

I think it should be possible to set up the MDL sounds in Dorico without too much trouble following these principles. Let us know if you run into further problems.