For those of you with a G26/27, what sleeve do you like for the 15 round mags?

None - I just use them as is for backup -

 

I do have some factory +2 extensions from Glock on my flush mags too, its a good in between with the G19 mag and the flush mag but still retains factory reliability and doesn't add much but you do get 2 rounds -

 

15's I just use like I do in my private escapades - bare

None. They pinch the shit of of your hands when reloading.

 

If I am using a full size mag, (which I always carry as a reload) I don't worry about a sleeve.

Sounds like "none" is the way to go!  Thanks guys.

None. They pinch the shit of of your hands when reloading.

 

If I am using a full size mag, (which I always carry as a reload) I don't worry about a sleeve.

Bingo

This is why I am avoiding sub compact guns.

Yup. If you are going to carry a sub-compact gun with an "extended" mag you may as well carry a bigger gun.