Another thought for your consideration.
Given the short length of the Shockwave and rear sling mounting location a single point sling, IMO, is a liability. If you're walking, running, working or bending over the Shockwave has a tendency to beat you to death plus the weapon is positioned perfectly to impact some tender body parts. The only way to secure it from bouncing is to hold it with one hand which defeats the purpose of the sling.
Using a two point sling you can securely reposition the weapon on your back or tightly to your chest.
Wonder if our OP disappeared?
Regards