In this post I have included a series of exercises using the intervals of a third, fourth.
I would suggest that you do the following.
1. Start with the interval of a second until it becomes easy for you at the faster speed.
2. Begin the intervals of a third at the slow speed until it becomes easy for you.
3. Begin the intervals if a forth with caution……
When I recorded this exercise, I was surprised at how taxing it was when compared to the first two exercises. I had a difficult time even recording it. Be sure that you have spent enough time on each exercise before beginning the next.
Good luck and let me know how you like these exercises…. (or don’t).