Those of you that have experience with 17/22 or 19/23 magazines in their 26/27's.  Do you use a grip adapter on the magazine and if so which one?  So far I've only found 2 out there advertised.  One of them specifically mentions a screw to keep the adapter in place on the magazine.  Does the screw go into one of the holes in the magazine that is used to display rounds remaining?  hmmm....  That could interfere with the mag spring, probably not then.  Seems that screwing into or against the mag body wouldn't do the mag any good...

Thanks again for your considered responses.

The screw does not go into the indicator holes.  It is just a set screw you tighten to keep the sleeve from moving up the magazine body.  I use a 19 mag w/ sleeve in a 26.   Higher capacity without the longer barrel protruding OWB.  When I want a smaller package I go back to the 26 mag.  You don't really "need" the sleeve, but I like it on my carry mag for holster draw.  The 19 mags feel fine just by themselves after reloads.

Edit:  Not sure what brand I have.  My range had them for sale and I bought it on the recommendation of a few friends who had positive things to say.  Works well but again, not required.

A&G makes them.

Photo is a link.

I use the A&G sleeve for G22 mags in my G27 & it's great.  The sleeve is tight enough that I don't even bother w/ the screw.  Found it was a pain in the butt to try to use the screw anyway.