You can't use 1/8, 3/8, 5/8, and 7/8. You can use all halves, thirds, fourths, fifths, sixths, and tenths. You can also use all eighths with even numerators (2/8, 4/8, 6/8, 8/8), because these can be used on a single track or can be converted to sums of equivalent fractions and then used on two or more tracks. The other eighths cannot be converted to a sum of equivalent fractions that could be used on one of the available tracks, as any such sum would leave at least 1/8 remaining, and the eighths track is already full.