Dual arc for sure. The adjustability improves the performance of your bow and quiver and costs VERY little in added bulk.
I adjusted mine
1) To alter the balance of the bow so that the upper limb very slightly rolls back when shot so I don't have to grab the bow after the shot as much,
2) To contact the bow closest to the grip as possible so as not to alter the tuning by affecting the working limbs - my bow shoots the same with and without the quiver.
3) To angle my hood so that I can hang it by the loop in front of the limbs without bumping my glass.
4) to angle the feathers to stay inside the strung profile of the bow at draw so they don't bump stuff when hunting
5) To raise my nocks as high from the lower limb tip as possible so the feathers/arrows don't brush on leaves when I rest my bow on the ground or my foot
6) To spread my fletching out just far enough for the fletching to clear each other so they don't make that velcro noise when drawing another arrow but not too spread out to reduce area of fletching to worry about.
That level of adjustability simply can't be matched by any other bow quiver that I know of. And, it's a fantastic quality product that can be made to match your bow.
I asked for my hood to match the cocobolo and yellowish tinted bamboo limbs under the glass with stitching off white to match the sides of the bamboo not under glass. I e-mailed them pictures of my bow in various lighting. I think they nailed it...
In late afternoon light...
Mid-day...