I have 'searched' the archives prior to posting. I am looking to visit Singapore for a week or so in the March timeframe, the itinerary(ATL-SIN) has NW metal from Toyko-SIN, can I use a PMU on this itinerary? (with Y/B/M of course)

On another note, can someone with EF so kindly check Z availability for the anytime in March on DL flights 55-3501, and 56-3500 (ATL-SIN / SIN ATL, via Toyko) Having never used PMU's, if there is Z availability on a particular flight, how far in advance will the upgrade clear? At booking? I apoligize for my ignorance in advance...

Peace