Before buying one way in coach, look at transferring SPG or AmEx MR into SQ miles or buying SQ miles to redeem the other direction in business class if you can do it for reasonable fees.

If you really want to splurge and have a fantastic experience, you could buy miles for under $4000 and redeem a RT in FC/Suites, but the additional taxes and fees could be high.

If you do only part of a trip in FC, try to depart SIN in FC with a long connection (or originate in SIN after a stopover) so as to be able to use TPR, which requires an outbound ticket (including any award ticket using SQ metal to leave SIN in FC/Suites) on SQ in FC/Suites or very high FF status on SQ.