I own and operate 72" Hustler HyperDrive mowers and cut at 15 mph a percentage of the time. I use nothing but OEM Hustler Fusion blades or Gravely Fisher Barton LaserEdge blades, and neither of these blades leave anything uncut, and I mean absolutely nothing.
When and if unable to get a much slower, smaller 42" Raptor deck to cut anyway other than perfect, you have one of several problems. RPMs of the engine need to be checked for proper speed, the blades need to be sharpened or changed, the deck should be checked for proper pitch and level side to side, and the spindles should be checked for bearing problems. One or more of these problems can cause stragglers to be left uncut, but in all reality a 42" deck should leave a perfect cut.
When and if unable to get a much slower, smaller 42" Raptor deck to cut anyway other than perfect, you have one of several problems. RPMs of the engine need to be checked for proper speed, the blades need to be sharpened or changed, the deck should be checked for proper pitch and level side to side, and the spindles should be checked for bearing problems. One or more of these problems can cause stragglers to be left uncut, but in all reality a 42" deck should leave a perfect cut.