Tuning Installing a sling on M3

I am looking for suggestions on how to install a sling on a M3 I have currently the Saber Tactical rail and bag rider installed. I would prefer a single point sling and I found a you tube video of a gentleman from Michigan who mounted his on the pic rail on top of the gun where the scope mounts to but I am a little leary of putting tension on that rail. please post a picture if you have a sling mounted. 

FX M3 and iguanna .1646097519.JPG