I bought all B747 performance files after his forum was closed. I wrote him an email, paid a couple britsh pounds via paypal and immediatly received the files I wanted. He was very, very friendly to me.
Speaking from my 15years PFPX experience by far the the most realistic and accurate Performance files for the 747-400F/-8F. Searching for the Flights optimum CostIndex actually does what it is supposed to do by entering 'Airport Fuel Cost', 'Var/Hr Cost' and 'Delay Cost'.
Unfortunate the PMDG 747 is incorrerct in flying costindexes but i have perfectly set the fuelbias in pfpx with airlineperformance.net files to fly at LRC Speed and the difference from T/C to T/D is +/- 100kg on 12hours flights. Mach and TrueAirspeed are spot on for most of the 747 variants. of course provided wind/temps are correct. This was not possible for me with the default PFPX performance files or others.