No. 30 can be practiced at a variety of tempos, although I settled somewhere around quarter note =54-60. The Cornopub edition suggests eighth note=92-126, and also numbers this particular etude as 31 rather than 30. In fact, No. 30 in the Cornopub edition is No. 33 (Adagio) in the Chambers edition. Looking a bit further into this discrepancy, the IMSLP copy of the first edition follows the same order as the Chambers edition. Perhaps Cornopub changed the order to give the player a break between etudes with large interval leaps?