What you are seeing here is Freddie Gruber's, Ruff to Roll chart. This is an flow drill that Freddie organized using the Buddy Rich Modern Interpretation of Snare Drum Rudiment's Book. Each individual component was worked on at length and only then did he start to organize the Ruffs to Rolls. The whole chart took many months to complete to satisfy Freddie. It must also be noted that you can play this exercise using any grip you like as long as you understand the hand motion of that particular grip and where the balance point are in relationship to the stick in the hand. I am starting with a 13 stroke roll as a reference point because I have to start slow enough to build up to the 13 stroke roll. See? Too fast you won't be able to play the entire exercise. Although the 13 stroke roll was the last piece of the puzzle in completing this chart. What makes this chart unique is the hand motion. The hand motion if you notice stays the same for the Ruffs and the Rolls. The basic stroke here is (down-up-tap) this was intrinsic to understanding Freddie Gruber's approach to hand motion. You may notice here there is a modified Moeller stroke with some sleight of hand stuff happening in-between the up and the down motion, that being the "Tap". This chart took many hours to put together and what you are seeing here is the end result. The student must understand the grips, the releases, and the balance points or fulcrums as well to play this sequence with the proper sensitivity. You could practice with or without a metronome here. I prefer without because there is a built in natural feel and sense of "real time" based on the hand motion when done correctly.
"A man with no form, no shadow, turns into a rice pounder when he pounds rice."
-- Bruce Lee