R7 TP = cast heads, pretty forgiving, hard to bend for loft/lie due to being cast (but can be done, but be careful), more durable for the long haul
755 = stainless steel forged heads, pretty popular on tour, "finish" quality isn't very good and they look like crap pretty quickly, will bend easier.
Soles on each are very different, try each in your type of grass to see which works through the turf better.
Rifle "flighted" means that the shafts have varying kickpoints to achieve different ball flights:
long irons are "low kick" to create a higher trajectory and short irons are "high kick" to create a lower more penetrating trajectory.
5.0 is a "firm" flex, 5.5 is more a stiff flex in rifle.