How much one can see at "last legal" light depends on a lot of things. I have been at places where I was well ready to pack up before the clock said I had to and places where I could have hunted half the night away. The amount of illumination, tree cover, animal color (those dam black bears seem to just suck in light) background cover all matter as does the viewers eyes.
Can a scope help.. sure one only needs to have used one that was a hindrance to know there are better or worse choices. Whether the cost for best low light performance is worth it depends on the user. When I say costs, its not all just dollars, your likely pay in terms of scope price, size and weight as well.
To the OP who was wondering how the weaver 8x56 would work as compared to other scopes in the same price range. I would see if I could buy one from a place with good return policy and run some evening tests, next to your current rig. No need to mount it, and if its no improvement, back it goes with out a mark on it.
