Best value i've got was on DFW-LGW-IAH which cost US$600 for the ticket - what a bargain! It was this time last year, and obviously either I talked to someone not au fait with the "you can't MFU a journey starting outside your country of residence" rule or the rule didn't exist at the time.

I find availability for HKG isn't that bad (especially for mid-week), and quite often opens up closer to the date of the flights, probably owing to the capacity on the route. I also find that J on this route is definitely what the doctor ordered because of A) the duration of the flights and B) the fact they're both overnights (i'm sure JimmyTheJock will agree!). As a silver you'll earn about 18,000 miles for a T-class return too, net cost 22,000 so not all that cheap but well worth it.

EWR's usually more open than JFK, unless you do MAN-JFK which always seems to be a suggested option when you try and quote LHR-NYC.