I shoot a lot of head shots on deer and pigs. Used a 3-9 forever and only turned it down much below 6 right at dusk.
All my shots at calm, still animals I always cranked up to 9 for head or body shots. 8 oughta be fine for me for what this scope will be for. Late afternoon and night pigs and doe deer. I have to hunt the pigs at 300 plus yards on pipelines and beanfiels sometimes and 8 oughta be enough mag to make a good shot up to 400.
Just need it to be tough and gather as much light as possible. Weight and size isn't an issue. But it will get bumped around a lot and I'll have to crawl with it and it will get covered in mud and crap constantly. I want something as simple and bombproof as possible.