A way to improve MIDI integration is to use MIDI learn in Reaper to re-assign the mapping. Another option would be to check out one of the scripts which enhance the Mackie Control integration with Reaper.

We suggest DrivenByMoss for Reaper as well as Klinke script, either of these will help expand your functionality within Reaper.

 If you ever need to locate the scripts for Reaper for  your device. It is located in the downloads tab of the main menu of the  QCon Pro X home page.

QCon Pro X Custom Script for Reaper for MacOS by DrivenByMossQCon Pro X Custom Script for Reaper by Klinke (Windows Only)