I thought CX's Y-to-J and Y-to-PE minimum bidding requirements on HKG-TPE and v.v. were way overpriced for an hour flight. I assume there are other data points on the CX board.
I have no insight to whether they offer J-to-F upgrade bids, but I would suspect you'd be looking at minimum bids on the order of $1,500-$2,500. (FWIW, that's about what Air France wants for its arguably superior La Premiere). The good thing is you'd be unlikely to be competing with many other pax at those prices!