While I've got a full-size 590A1, I've also got a similar-to-Shockwave Remington Tac-14.

The MesaTactical "LEO" grip adapter for the Mossberg (& Remington, which is what I have/had) has built-in "QD" sockets. You paid a lot for that grip/brace adapter with QD sockets and I say use 'em.
I use a Magpul MS4 sling with dual QD swivels:
https://magpul.com/catalog/product/v...obal_color=118
This sling allows either 1-point or 2-point attachment methods. For a 2-point, you'd have to figure out how & where to attach the forward QD sling end on a Shockwave. I prefer using a mag tube end cap with a sling-mount and not the pump/foregrip.