So MSD's last transfer offsite was to the 270 Park avenue redevelopment for 666,766 sf...
So it works out as :
Base FAR of 15 for the GC lot (not including the Hyatt) = 2,198,700
Amount of built space currently on the lot = 322,664
Amount of previous transfers = 491,026
Transfer to 270 Park Avenue - 666,766
Remaining development rights on site - 718,244