3rd Gen grip observation I'll share.

[BAM-BAM]

First IMO grip fit and feel are subjective to each individual shooter.

While I prefer straight back factory grips on my full size 3rd Gen guns (5906,915); I like the curved backstrap on the 69xx series of gun. On single stack guns in the 39xx series I prefer the slightly thicker and curved backstrap of the Hogue wood or rubber grip to the straight back factory grip.

Interesting observation this week, after shooting the 3rd gen guns for over 30 years.

Background.... Hot and humid here this week so decided not to carry IWB while walking the dog. So I got out one of my reverse two tone Frankensmith 6915s ( 6906 frame mated to a 915 slide) and a Bang-Bang Leather pancake holster w/ full sweat shield . I normally carry this gun with a 12 round mag w/ finger extension and carry a spare 15rd mag with a +2 adaptor.

For S---- & Giggles I swapped the mags and carried it with the 15 rd mag w/+2 adaptor. So in effect I've had a 5903 size gun... 4" barrel, full hammer, alloy frame w/full length grip.

In administrative handling and a quick range trip I really liked the feel and handling of the 6915 with the +2 mag.
When I got home I pulled out a set of factory arched 59xx grips. Comparing the 59xx grip to the 69xx the 69xx grips don't "appear" to have as much arch as the 59xx grips; and the +2 adaptor on the 59xx mag gives the full grip a "bobtail" look and feel.

Only had the FrankenSmith 6915 for a few years and when I've carried/shot them they were configured as a CCO with long slide and short butt to carry concealed IWB..... only used the 15 rd +2 mags at the range for tactical reloads.

Anyway I really like this combo; historically if I wanted a full size 3rd Gen gun I'd grab a 915 with a straight back grip..... in the future I can just swap mags in the 6915. If you have the chance ..try it you too might like it!!!

While few have a Frankensmith 6915.. it would be an easy way to "build" a 59xx SSV.......

 

[stansdds]

I think your analysis is spot-on. Yes, there is a difference in the curvature between the 69xx stocks and the 59xx curved back strap stocks.

The curve in the 69xx is such that it nicely fills the palm of my hand and my thumb is perfectly positioned in the concave area. The curvature of the 59xx stocks continues further down the stock and the apex of the curvature is positioned lower on the pistol frame than that of the 69xx stocks. It creates a different feel between the two pistols.

I do not own, but I have handled some 3913's and yes, the grip area does feel too small, even for my medium sized hands. The same goes for the single stack Glocks, they feel a little too small and if I am going to put on a stock that pretty much duplicates the size of the factory 69xx stocks, I might as well carry a 69xx pistol, which is what I do!

 

[BAM-BAM]

I live in a very quiet Burb of the Burgh so my EDC is generally a 3913NL with a flush fit 7rd mag (originally shipped with early 3913Ladysmiths) + a spare 8rd mag. With a set of Hogue checkered Wood grips which gives me a curved backstrap and a "bit" more thickness (think palm swell). The smooth Hogue grips are a "bit thicker" than the checkered grips. The NL has a single side safety. In a Milt Sparks Executive Companion holster that carries the gun lower (and with a cant} than their Summer Special it's been very conceable over the past 30 years The wood grips don't drag on clothing like rubber and the checkering give a superior grip. Overall it's a "bit" smaller and lighter than a 6906.

Generally if traveling away from home base I'll switch to a Performance Center Shorty-9 (6906)..... 12+1 + one (or two) 15rd+2 mags..... that I've had and carried since the mid-90s. Again carried in an Executive Companion Holster.

Spare mags are carried in horizontal mag pouch that ride on the belt.... for the double stack mags it's a Safariland 123 synthetic . The one for the 3913 is a custom made leather.

 

[RufusG]

Needs pics!

 

[Walter Rego]

My Model 1006 came with the factory straight back one piece grip. As I prefer arched mainspring housings on my 1911 pattern pistols I tried the factory curved back grip and never looked back.

 

[BAM-BAM]

As I said in the OP everyone has their personal preferences; hand size and finger length varies.

The single stack 1006mm is the same grip frame as the 4566 I have which wears Hogue rubber grips with the curved backstrap. Rarely carried but my favorite Smith .45. For me carry .45s are alloy frame Sig 220 or the Compact 245.

The best example is the revolver "Combat"/ finger groove grips. They look cool on every gun I've ever seen them on. Some folks love them... they don't work for me at all... they force my little finger away from my ring finger weakening my grip. But Spegel Boot grips are on all my carry revolvers.....J-N frame!

Find what works for you.... why a lot of us who've been at this for decades all have a Big Box of Grips and a "Big Box-O-Holsters"