The following coins are the ones that lose the least amount of time. You can collect these coins or use some of the alternates instead. Just make sure to have at least 5 coins before reaching the levels that require you to buy them (1-A, 2-A, 3-A, 4-A, and 6-B). Once you buy 6-B, star coins no longer matter, so don’t worry about collecting them.

1-1: 1,2 (2) 1-3: 1 (3) 1-T: 1 (4) 1-4: 1 (5) Buy 1-A (0)

1-Ca: 1,2 (2) 2-1: 3 (3) 2-2: 1,3 (5) Buy 2-A (0)

2-A: 2 (1) 2-GH: 1,2,3 (4) 2-Ca: 1 (5) 3-1: 1 (6) Buy 3-A (1)

3-A: 1,3 (3) 3-T: 2 (4) 3-4: 1 (5) Buy 4-A (0)

4-T: 1,3 (2) 5-Ca: 2 (3) 6-1: 1 (4) 6-2: 1 (5) Buy 6-B (0)

Backups/Alternates: 1-2: 1 1-3: 3 1-T: 3 1-A: 2 2-1: 1 2-T: 3 2-Ca: 2 3-1: 2,3 3-Ca: 1,2 4-1: 3 4-A: 2 4-3: 2,3 5-T: 2,3 5-Ca: 3 6-2: 2