How many turrets per acre? Would 80/a deter attacks?

It would depend how far into the set and what server. In reality it is much more about your turrets vs countries with similar land as you. You should not be in the bottom 5-10 of NW/Land ratio.

I have heard ratios like 100:1 but I believe it is much more relative than that.

there's no absolute answer like andrew said, as long as you are around same nw as others who have near same amount land you are quite fine but there are always those who will grab you no matter how good defense you have.

If you are the one with the lowest DR on the list, you can get grabbed.

Also, you are more likely to be grabbed if you are not capable of retaliating.

and even if you are capable to retaliate you'll get grabbed since attacker counts that you won't get your losses back.

I have a nuclear capability to retaliate but not much else. Curiosity is getting the better of me and my spys are smokin too much chronic!

I understand what you're all saying, but hypotthetically speaking - At 7000 acres would a million turrets put off any attacker out there (with the same acreage). I know you can't factor the complete lunatics. Any attacker wish to reply?

right now, probably. in 2 days time probably not

1m today, 2m next week, 3m after that, etc.