This is tough. I tried doing this on my own for a while. I remember the tricks I came up with were minimizing "fucking around" time so I could get extra time bonus and six fireworks, also with the turtle shell glitch where it ricochets offscreen and comes back to give you 8000 on the last goomba. Probably in the video, just saying I figured that out a year and a half ago
Totally by accident but after a little practice I did it each time through.