That was the video I watched, yes. The first time I watched it, I was away from my friend and couldn’t test it out, and on subsequent rewatches while trying to get it to work, I skipped over the all-important step of adding a track specifically for the mapped instrument.
I thought the tutorial was excellent but the time spent on arranging the tracks and windows just so visually, made me impatient. This was my downfall; but thanks to you I rewatched again to make sure I hadn’t missed anything and voila. My mapped instrument works perfectly for my needs.