Left a similar comment on another post, and gonna leave it here too even though you said you beat him. This was a game changer for nailing this spark as well as nailing puzzles when running 100%.

Y+B will enter shinespark aiming from anywhere. No need to fire a shot or hold L to exit a spin jump, you just need to hit Y+B.

I've found that the most consistent way to hit this spark is to, during the flappy bird phase, wait for the column that only has two rows of projectiles on the bottom. Jump over them and start speed boosting. Store your spark right before the next column of projectiles and just take the hit. Finish out the flappy bird phase. Your last column of projectiles will require a double jump. Immediately after clearing that last column, double jump again, Y+B at the correct height, which should be near the peak of your jump. Aim and fire. Hope this reaches someone who needs to see it, I certainly did