Really comes down to personal situation; how important is your travel on the exact dates; how important is the exact location; how flexible is your budget etc etc. If you have to be in TPE on those dates, I'd make my hotel bookings etc. Back up plan would be paid Y and I'd have a limit at when prices got to a certain level I'd pull the plug.
Others would waitlist a load of flights to TPE, have alternate reward flights available, and have 3/4 days departure flexibility.
SQ waitlists can often clear in the week before travel and up to day of departure. I get limited holidays that must be booked well in advance - losing 3 or 4 days waiting for a flight to clear doesn't suit me.
Check out the milelion page if you haven't before, he has a few articles on the waitlist in the directory.
Experimenting with the SQ Waitlist | The MileLion