1. if you have 80% chance of being a band 1 student, regardless it is at the low end of band 1 as long as it is 80% sure to be in band 1, one should consider to fill in 3 band 1 schools before the best band 2 school.
2. however, if one only has 20% chance of being a band 1 student, one should only fill in one band 1 school as the first choice which might only have a few places and not the hot-picked band 1 school. thereafter, the second and third choice should consider the band 2 school to play safe.