That is a question you should pose to a good fitter. Every shaft has it's own characteristics, and the stiffness designation is meaningless when compared to any other brand or model. I know not everyone can get to a true club fitting, but if your serious about improving your ability and performance, you should try to arrange it. You would be amazed at the difference the right shaft can make in your swing.

We can only guess, not seeing your swing or TrackMan numbers. You can always go to a fitter and compare numbers. If there is a significant difference, maybe reshaft or consider the new irons when they come out this fall. You want to make sure that a distance improvement does not significantly impact your dispersion numbers. Taking one less iron but missing greens or putting from 50 feet is never the answer. Good luck!

First, you may want to be sure you are mostly rehabbed as best you can expect. If you are still not seeing the results pre-surgery, then sign up for a Titleist sponsored fitting. The $100 fee is put towards with a purchase that day.
Titleist prices their products per club, and the price per club is the same whether you buy from a retailer or direct from Titleist. Or a set off the rack. Why guess when you get a free fitting (with a purchase that day)? Likely a softer flex will help, but that is not a guarantee and likely not optimal.