Invert Roll and Fortepianos are two exercises that I used with the 2014 WSIP snare line in order to work on doublestrokes, with a silly fill to mash the two together. I like using inverted rolls to work on doublestrokes because it puts the second note of each diddle on the eighth notes, where weaknesses will be more obvious to the ear. The focus of both exercises should be matching comfort and sound quality between the forte diddles and the diddles at the tap height.