I have a NAN-SFO RT coming up in mid May and the Bula bid range is currently $905 - $1735 each way. Anyone have recommendations on how much I should bid to have a decent chance of snagging the upgrades?

Edit:
For any who may be interested, I ended up withdrawing my Bula bids (I had bid $1300 each way for NAN-SFO and SFO-NAN) 2 days before the flight, after I saw the economy cabin was about half full. In the end I had nobody on the seat next to me for either flight so it all worked out. As a data point, I was quoted $1400 for the upgrade at check-in for NAN-SFO. For SFO-NAN, they didn't want to offer me an upgrade due to limited catering in business class, the GA said that she would have to get approval from her manager to do it and it would likely be around $1600 to $1700. All prices here are USD.

As an aside, the service and friendliness on board the aircraft (in economy) and at check-in, at the gate, etc. was phenomenal. Perhaps the best on any airline I have flown, and definitely better than the major US carriers.