I want to accomplish the same task, it's in my TODO. There is no way to do that task with Mididings without an OS to MIDI layer. Your approch is correct. But you solution is tight coupled with Jack backend.
On my side, I work with ALSA.
It's an uni-directional OSC to MIDI gateway. It open a virtual ALSA MIDI ouput port and listen for OSC messages on UDP port 5555 by default.
I will connect this Virtual Output port with Mididings