Hi, I'm planning to burn some miles after my graduation which is scheduled to be on May 31st. I'm planning on IAD-CAN with a stopover in SIN in C cabin and return in the last two weeks of August. I'm trying to avoid United when redeeming my award miles and to book on Asian Carriers like SQ, NH and OZ. Does it violate redemption rules to go IAD-NRT-SIN-CAN? Because this is backtracking in the map.

And as far as I know SQ rarely releases award seat in C on its long-haul flight. Is there any long "regional" flight that SQ releases C award space?

Thanks
Ben