While there are many solutions, the fastest solution is as follows:
By sidehopping as you complete the Isle of Songs Puzzle, you can skip the cutscene that plays when you solve the puzzle, thereby saving 3-4 seconds.
The route below is the fastest known route for spiral charge, able to get a time of 76 seconds remaining.
The Bug Wrangler mode of Bug Heaven is required during 100% runs. The following route, if done perfectly, can get times under 50 seconds, and can be consistently done in under a minute.
To increase your odds in the Fun Fun Island minigame, use the following strategy. As you pass through the final ring, find your target spot on the circle below you. Treating the board as a clock, aim for the spot three hours later on a clock. Then make adjustments as you come in to land.
For example: as you pass through the last ring, the 50 rupee space is at the top of the circle (12 o'clock). Aim for the right side of the circle (3 o'clock), and then make adjustments from there.
For the adjustments, when you are skydiving the more you move left and right, the faster you will fall. So if you have to move a lot to reach your target area, you won't have to make many adjustments. However, if you don't have to move at all to reach your target, then you'll have to make more adjustments as you fall.