No. 49 is an excellent study for developing a consistent sound and accurate intonation in and around the mid-low range. Changes in air speed and jaw position are very helpful in tackling the large leaps. Try playing the entire etude on the B-flat or F side to help learn the different intonation tendencies for each set of fingerings. Tempo range in my edition is quarter note=66 to 84. A slower tempo will work, but breath control can become an issue, especially in the lower range. *Apologies for the unusual formatting of the video (black box around the video). I was trying out a new setting when converting the footage from my camera into a format that Adobe Premiere could open, and unfortunately it resulted in the weird formatting.