I bought a sling swivel for the top rail. Much like the one you show and use the rear point for the other end.
With the sling over the shoulder on the LHS and shottie held by the pistol grip and left hand on the bolt it can be worked fast shooting from the hip.
The red dot is high enough the sling swivel does not bother me. Yes they are hard to carry as the mag is at the point of balance so I ordered one of those rail carry handles as well. Should be here tomorrow.
Front sling swivel is well forward but enough room for a laser for hip shooting. Just for fun.
I had some Lyman slug loads I made up for the Adler with its rifled choke. They shot well in that but wont group with this and its IC choke.
Bought several 5 shot packs of slugs from Rebel. Different makes and types . $60 freight by Courier to get them but no option. See how they go next week.
I am in QLD.