I can’t speak for all manufacturers, but some will use 8 iron specific shafts, trim them and brand them as a wedge shaft. Others will simply develop a wedge specific shaft for whatever kind of performance they are trying to get to. Better players will experiment, a lot, with different wedge shafts or iron shafts trimmed a certain way to get the performance they are looking for based on their own attack angle, ball type, etc. Several schools of thought on wedges, whether they should be more flexible (my view) or stiffer than the shafts in the irons. Still, to each his own and you just have evaluate and test to get the right trajectory and spin for your game and the conditions you play in.
Britt Lindsey
One method I’ve seen with a very high success rate is using the 8 iron shaft of the next stiffer shaft for wedges— ie using DG S300 for the iron set and then using X100’s for the wedges. There’s a few YouTube videos out there that show a significant increase in spin (around 1000 rpm) and a noticeably lower launch angle (minus 3 or 4 degrees).
That being said, I don’t really understand how this is achieved lol. It would seem to me that soft stepping a stiffer flex twice would get you into almost the same flex as wedge trimming the original. Also, I realize your question is aimed at getting some insight into the characteristics of wedge specific shafts. But due to this confusion around them, I try to avoid them altogether and stick to what works for me. Unless of course I’m looking to hit a specific weight or higher launch in the wedges.