Iron Swingweights - D6 and above

Sharing what I have been experimenting and most recently with Tourstage Z101.  Background, its an old tourstage and one the last that was forged in Japan.  What interest me was that I fitted it once with graphite and I couldnt do jack with it.  I mean, I was lucky I could do 90m with 9i, and no kidding!

Then, I traded the graphite shaft with KBS C-taper which was 1/2in longer and when installed, the swing weight ended up as D6 or D7.  The interesting part was that i can really hit them well enough that i dont feel that i need to kill them balls.   Question is why?

So, i google about the subject and noted this 2 comment:

- "Tom Kite and Lee Trevino both suggest that most amateurs should hit much heavier swingweights than the standard range of D-1 to D-3 that most manufactured irons use. The reason for this is their lack of acceleration through impact."
- Swing Weight = feel and everyones threshhold for this is different. A D-2 might feel really heavy to a slight person where D-6 might seem like just barely enuff. The important thing is that enuff swing weight allows you to feel the club and thus route it more consistantly thru impact and voila, better results.

Can this be true or it is an individual preference?

Or can it be the longer shaft length is a better fit for u ?

Interesting. Thats why we sometimes shldnt just buy what the major golf retailers pitch.

Same myth for playing with blades meant for only low HCP'ers, scratch golfers.

it could be the total weight as well

Whether its 1/2inch or total weight, having a heavier swingweight, is it a bad or wrong thing?

Still preference. I liked my irons better after I cut them and play to d0-d1. Previously it was d4-d6 and 1/2 inch longer than std and I duffed a lot. Now I hit it thin a lot but thin is better than duff