I just got my first triangle folder and fitted/installed it on my rifle. I found an old write up about using an IWC sling cup installed into the sling loop hole on the stock and it seemed to look and work ok.

I found two others that I think would give a more "finished look. One is made by noveske and the other is made by grovtec. My only concern is the flange or nut being too large and overhanging past the area it would need to seat properly.

Has anyone tried one of these type?

Just for reference so you can see what I'm referring to.....

Grovtec:
https://www.brownells.com/shooting-accessories/slings-sling-swivels/tactical-sling-mounts/push-button-base-for-hollow-stock-full-rotation-prod119848.aspx

Noveske:
https://www.opticsplanet.com/noveske-flush-qd-sling-mount-black-05000471.html