For the Line Trial, use Kirby and get the Burning power-up. When you get to the part with a bunch of ledges and you must get to the top, keep tapping Kirby. He will dash into the walls and climb up the walls. You will have to use some ink to get to the end. Once you can't do this any longer, get rid of the Burning power-up then use two simple lines to reach the goal. You should make it in better than 800 ml if done right.