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How do you figure out which slings are right for your needs?
First you determine what your needs are which you have already done a pretty good job of below. Then you choose the appropriate sling to meet those needs.
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I do not need a muzzle down non-agressive position, only a comfortable all day semi-relaxed position that supports some of the weight of the carbine in front of the body and deploys quickly.
Your needs as outlined above seem to indicate that a quick adjust two point sling would be ideal for your application.
If you need help choosing components for your weapon platform or have any further questions, please don't hesitate to let me know.