Loft and shaft length in determining distance?

[LuciusWooding]

I'm in the market for new irons, and I've decided on getting Gigagolf GX922s, clones of Callaway x22s. Their sheer price advantage over any other set I've seen has sold me, as well as the good fitting options.

The problem is that their online fitting relies on the 5 iron carry distance to determine swing speed, in turn determining rough swing speed. I play very old titleist irons (AC108) that are too short and beaten up, and their lofts and lengths are quite different from modern lofts, a club different or more. They also have odd gaps in length and loft, particularly below the 7i.

I learned how to hit my irons over 9000x better in the last few weeks, and picked up a fair bit of yardage as well as better gapping. I hit my 5 iron an honest 165 carry on average, but my current 5i has a loft of 30* and 37.25" length, as opposed to 27* and 38.25" for the new 5i (I included the .25" length increase due to my height.)

I imagine, as a result of the new set, I should compare my 4 iron, which I hit about 170-175, and has a loft of 28* and length of 37.75" to a modern 5i? Even then, it seems like the .5" and 1* difference will add even more yards. This is in addition to the modern technology and fresh grips (Which I can feel slipping pretty often), as well as a fair difference in swingweight. I've never hit a modern iron, clone or not, except my dad's SW to bump the ball onto a green once; hardly a full swing.

So with all that said, would it be unrealistic to expect to hit the modern 5i something like 180, or even closer to 190? The shaft flex calculator is approximate, of course, but wouldn't it be based on modern Game Improvement irons?

And if the shaft flex calculator is based on modern clubs, should I go for a stiffer flex? I decided on firm flex steel shafts, which recommend a SS of 75-84MPH. I've never had my SS measured, but even the old 5i's carry distance is within a few yards (168 is the minimum) of firm flex. I do have a high enough ball flight and left tendency (though I'm really pretty straight unless I try to draw it too much) that stiffer flex wouldn't hurt me, and I like the feel of a stiff shaft. My driver SS is in the ballpark of mid-upper 90's, so a stiff flex on woods is a given depending on the specs of each shaft.

I shouldn't assume that I'll hit new clubs way further than older ones, but I'm talking a 40 year old set vs a modern GI set. I can't see how I wouldn't pick up at least 5-10 yards, even if I ignore the names of the clubs and compare similar lofted clubs. My decision for now is to get one or two individual irons built to my specs, probably a 5 or 6 and a GW, and a Fairway wood (to get the order over 100$ and ship free), and see if my expectations are right.

On a related note, anyone try the Winn V17 AVS soft midsize grips? My current grips are, for lack of a better term, fossilized, with the exception of the 5i which got replaced at some point with a rubber grip which remains tacky. As a result, I hit the 5 much better than the 4, even with a glove on. My main concern is a combination of durability and feel. I won't likely replace the grips as often as suggested, especially due to the pricy nature of the Winns, so their ability to stay soft and decently tacky is important.

Anyone who made the change from 70's irons to modern ones, or is a fitting guru, I'd appreciate your input. The older irons are not exactly blades, but don't really have a proper cavity either. I know I can expect a fair bit more forgiveness, but I'd like to figure out a good set build without excessive distance gaps, and I need to know what to expect from the biggest part of my set.