A triplet fill that keeps the pulse audible is worth ten that bury it. The six-stroke roll gives you exactly that: six notes, R L L R R L, laid across two beats, with both of its accents landing square on a beat. Your hands run triplets and the listener still hears quarter notes. Vinnie Colaiuta and Dave Weckl live inside this phrase.
Exercise 1A runs two reps per bar in 8th-note triplets, one triplet group to a beat. Count it 1 trip let 2 trip let: the accented R hits 1, the LL double fills trip let, the RR opens beat 2 with its first note accented and its second one a tap, and a quiet L closes the phrase. Those two accents are positions 1 and 4 of the six, and stripped of the sticking they are ordinary quarter notes. What makes this a six-stroke roll rather than accented triplets is the pair of doubles threaded through it, the LL falling between the accents and the RR beginning on the second one. Because the phrase ends on L, the right hand leads the next rep with no flip to think about.
Learn it flat before you learn it loud. Play the sticking at ♩ = 70 with no accents at all and listen for six evenly spaced notes, because the LL is the pair that collapses first. It sits directly behind the loudest note in the phrase, and under pressure the two left strokes close up into mush. Then add the accents and set the click on quarter notes. Every accent should vanish into it, and when one lands early or late the fault is uneven triplet spacing ahead of it, not the accent itself. Get 1A clean at ♩ = 80 before you take it to the kit; ♩ = 90 is the top of the practice range, not the gate.
Sending the accents to the toms
Exercise 1B keeps the sticking note for note, settles at ♩ = 76, and re-drums only the accents. The first accent of each rep goes to the high tom and the second to the floor tom, which across the bar means high tom on beats 1 and 3, floor tom on beats 2 and 4. Every unaccented stroke stays home on the snare, so the left hand never leaves it for the whole bar. Underneath, the bass drum plays beats 1 and 3, so each high-tom accent arrives with a kick while each floor-tom accent arrives alone. That foot is what keeps the phrase reading as a fill laid over the time rather than a tumble down the toms.
One stroke does all the damage: the second R of the RR. Its partner is the floor-tom accent and it lands back on the snare, so that double cannot be a rebound. It is two placed strokes with an arm move between them, and at ♩ = 76 you get about a quarter of a second to make the trip. Start the move on the way down from the accent rather than after it, keep the tap wrist low, and let only the accent arm travel. The moment that snare tap lands late or loud, drop back to ♩ = 70 and rebuild.