I've found the GWR Gravity Master to be very ergonomic, more so than other more traditional G-Shock designs. Not square though, which I think is what you want.

 

How about this:

G 7710

 

Sadly, it is not in production anymore but one of the most functional battery powered G.

 

Among those Casio I have(square, frogman, protrek...), the PRW-60(as well as the same size of PRW-30\50\70) would be the most comfortable for my 15.5cm wrist(although it's not a G). I've changed a nylon band which is more friendly to the skin.

 

I find many g-shocks obnoxiously large also.
Pro tip: try on a few women's g-shocks.

 

The titanium g-shock squares are very comfortable on the wrist. The way the bracelet protrudes outwards from the lugs doesn't make it suitable for the very small wrists though. My wrist is 6.7 inches / 17 cm and i'd say that is about the minimum wrist size.

 

Baby-G

 

I hated the resin band that mine came with. I picked up a Barton rubber strap on the cheap and it totally changed the wearing experience. It's downright comfortable. Looks smart, too.

I know you wanted "stock" options, but you might be better off just picking up a rubber strap to solve your comfortability issue.

 

DW-5600 series (but not the solar/atomic "GW" models). GA-2100. Titanium squares (include solar/atomic).

 

Is any G shock “uncomfortable”

Yes.

 

greenmanito, Did you modify the Barton strap? What is the width you got?

 

Barton has one for G-Shocks, so no modification necessary.

Black Elite Silicone Casio® G-Shock Watch Band

Our Elite Silicone Quick Release black watch bands are now available for select Casio® G-Shock Watches. This strap features a premium textured top, a Black PVD Buckle, and a 2mm taper from watch head to buckle. Our new G-Shock Elite Silicone Quick Release Straps have been custom designed to...

www.bartonwatchbands.com

 

I vote for Baby-G also

 

PRW 60 is a pretty comfortable watch. I have a 6.75”/17.1 cm wrist and it wears very well, IMHO.

 

I find the GW-M5610U very comfortable on my 6.5” wrist; I’m wearing it right now!

 

If you can find one, G2900 is the most comfortable G-Shock I've ever worn, better than square. The strap does NOT have wavy serration.

 

I only can confirm that!

 

Try the S-Series G-Shocks like the GMA-S5600 or the GMA-W5600.

 

Try the bracelet on the 5610. If that bothers you, you're too weak to wear a watch haha.

 

GMD-S5600 is the smallest G.