Twilight factor matters when evaluating antlers in low light. For this reason, I lean towards higher mag when comparing similar exit pupil sizes (i.e. 10x42 > 8x32).
I think the ultimate optic for what you are describing on the current market would be the Swarovski NL 10x52. I'd love to own a pair some day. (But at 1000 yards you may actually need higher magnification for antler evaluation rather than just buck vs doe). The AK prisms Swaro uses for their latest SLC 15x56 does really well in low light and compare well to my SLC 10x42. The NL 14x52 is likely even better).
The 8x56s are a 7 ep. There's a chance your pupil won't dilate that large. Or won't for much longer as you age. So you might consider trying to figure that out before taking the plunge on the 8x56.