About the best F redemption I have done recently was YYZ-(AC J) - LGA// JFK-(OZ F) - ICN - (OZ J) - PVG - ( SQ J) - SIN- ( SQ F) - CGK - ( SQ F) - SIN -( SQ J) - ICN- ( OZ F) -JFK //LGA -( AC J)- YUL-(AC J) -YYZ..
I also did a one-way SIN-(TG J) - BKK - (TG-F) - NRT - ( NH F) - ORD - ( AC J) - YYZ a couple of years ago.
It's getting harder to find regional F flights to add on to the Transpacific F ones.