So far, I've found some variation of a standard 2-point sling works best for me. Methods of attaching the slings vary slightly on each of my shotguns. The Vtac-type slings, although being a 2-point variation, just don't work as well for the standard shotgun.
Something like this (thewilderness.com) works best for me along with the appropriate weapon handling techniques for this setup.
On the one you've pictured, I noticed it doesn't have the sling swivel on the barrel clamp.
A bottom or side mount, depending on preference, can work for the front, with a standard sling swivel
installed into the bottom or side of the stock near the buttpad for the rear mount point. Definitely use the side mount plate if a Surefire fore-end light is ever to be used.
You've already found out a drawback regarding the sling mount between receiver & stock, which might work for some, especially using a single point sling, but not for others.