I don't think the blades are as hard to hit as their reputation. Off center hits feels worse but the result isn't much worse than with a forgiving iron. I even saw a scientific comparison a while ago where they compared thin, toe, heel hits etc. The difference was very moderate, and the blades even produced better results on a couple of the mishits (i think it was towards the heel)
I wouldn't advice aganist blades for a 12 hcp. If you like what you see at address they will not hurt your score. And the feedback you will get could make you a better player.
But lie angle and shaft must fit or else it's just a waist of money. And I think the two should fit with how you want to hit the ball and not necessarily to how you hit it today. Particularly if you have a misfit today your swing has adopted to it and those compensations will also be in operation when you try new irons.
I went for Mizunos because they were the flattest forged irons I could find. Then I had the factory make flatten them progressively towards the 3 iron. I did the fitting based on experience and wear marks on my old TA 845SS (which was also pretty flat) and it turned out pretty well. If anything I should have flattened a degree or two more in the short irons too. And perhaps I would have benefitted from something slightly softer than s300 but I don't think that affects either scoring or workability so it's a minor.
Does the plane angle have influence on the lie angle? I.e. if want to set up close to TSP (for zero shift) than a steeper lie angle, elbow plane then flatter angle.
Yes. But perhaps not as much as one would believe. Where is your hands at impact and where do you want to have them? Then you have to account for the shaft flex. Stiffer shafts requires flatter lie angles because they will flatten less when CF is pulling the clubhead.
Have a look for instance at Fowlers impact vs Hogan's impact. They are both really flat after transition. The biggest difference is that Fowler lets CF throw everything on plane through impact, so there's an almost straight line from his Left shoulders through his hands and to the sweet spot. While Hogan's holds his form much longer and goes through impact with lower hands. Hogan needs a lot flatter clubs than Fowler. Or perhaps what we see in Fowler is adaption to modern lie angles?
In today's world of professional fitters, many specialize with certain companies. For example, I am a certified fitter for both Titleist and Ping. If you were in my area, I would be very comfortable custom fitting anybody with either. I would not feel comfortable fitting someone with Mizuno, as all companies specs are a little different, and I have no experience with them. I also wouldn't have Mizuno demos for you, and you would not be able to hit the various flavors.
I think most fitters are the same way. Someone who specializes in Mizuno may not be also certified with Titleist.
As others have mentioned, the most important part of buying new irons is being properly fit. If you have decided on Mizuno, a great choice, please be sure to find a fitter in your area who specializes with Mizuno equipment. You will be happy you did, and they will set you up with clubs that you will have a ton of confidence with.
Kevin
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I could be wrong. I have been before, and will be again.