Reading eighth note triplets is much simpler than reading quarter note triplets, since, like eighth notes, this figure is found in many styles of popular music, and this makes them fairly easy to assimilate. In any case, always recite eighth note triplets to control their location in the beat and the bar and place your strokes accurately (with confidence), and listen constantly to the metronome so that you do not lose the beat. Quarter note = 50-60. In this exercise speed is secondary to what you really need to accomplish here. Do not worry about having to play at very slow speeds; it is more important that at this speed you can assimilate the exercise properly, and then go on to speed up by 5-point intervals on the metronome until you reach your limit.