For HT, after HS, I have had success with students when I focus on ear training and counting. Similar to what you did with the record function on your keyboard, I play the LH along with the student playing RH, and vice versa. This seems to be very helpful to them, because they are listening to how the two hands coordinate together - and they already know both parts well, so they can discern what they're listening to and play accordingly.
Maybe this is too close to the highlighting method you show above, but it might help to draw lines connecting the notes when both hands will play together. Then, notice the "longs" and the "shorts". In this piece, the 8th notes are long and the 16th notes are short (and the quarter notes are even longer, played against 4 16th notes). Whenever you see a grouping of 8ths on one hand and 16ths on the other, then one hand is going to play by itself every other note. This will simplify the process, and help you to feel the rhythm.
For example, in the first measure, your hands will play the first note together, then count 2,3,4 while your LH plays alone. Then together every other note, and the LH will have notes in between. Repeat the same pattern for measure two. Measure 3: Together, 2, 3, 4, 1+2+, together, 2, 3, 4, 1+2+.
If you continue recording and playing along with yourself on the keyboard, you can listen for these patterns of counting. When starting HT, it will be slow, but do a measure or two at a time, with several repeats, and feel the rhythm. Pretty soon your hands will know what to do.