Spent a bulk of my day hitting irons at GG and EW. I believe I have settled on the iron I want, and the Mizuno Shaft Optimizer selected the TT Dynalite XP R300 for me. I can get that shaft in either iron I am looking at - the Mizuno 800 or 825.
I can also get the clubs in a Nippon NS Pro 950 GH shaft. I was NOT able to hit that shaft today, but I am wondering if it would be worth the extra cost for it. I was looking for a lightweight option, but am not sure how those two shafts compare.