I always use controllers to control the X and Y, it is a lot easier to have a controller lane (or VST Expression in Cubase) using controllers, especially as keyswitches mess up the score edit page. I don't try to change cells in real time, I record my track with one articulation, and then set the required articulations afterwards.
You could have single notes changing each cell, but you would have to have a one dimensional matrix array, so just using the X axis only, then each new keyswitch note, would select the cell, the only snag here, is that you may run out of notes, before the keyswitches collide with the playable area.