HDB usually give queue number up to 3 x the number of available units.
Personal single friend same situation as yours, got 2k+ queue , for 600+ units in punggol.
in the end still manage to go chose unit, and many high floor units left as well,
he chose above #15 if not wrong.
many singles applicant drop out, alot just apply for fun.
if not choosy , very high chance will get a unit.
-vinz