Sounds like the OP has chosen a rifle. And yeah, .308 vs .30-06.....tomato, tomatto.
A 3-9 optic will do nicely. 3X is still good up close in the deep dark woods (doubters, try it with an unmounted scope at say, 15 feet in your yard.) and 9X will provide ample magnification for long shots. I do not personally like 50mm objectives, 40 mm is enough for me. I don't find the extra few percent of light-gathering power terribly meaningful. To get an optimum 7mm exit pupil, (objective lens dia. divided by power) a 40 mm scope must be set to 6X, and a 50 mm scope to 7X. Those settings will gather all available light.
I'd prefer a lower-mounted, handier scope than that extra 1X power, especially since I don't want to shoot a looooong way in dim conditions.