to cant or not to cant please?????

[fedupflyer]

There's no need, until there's a need. My though is better to have and not need.

The other factor is how close the scope mounts to mechanical zero. He could luck out and have 18 mils of come up on a standard mount. Or he could crap out and just have 8 mils.

We've never installed a 20 and couldn't get it zeroed.

I was basing it on him having 80+ MOA of up adjustment or 170 MOA of total travel and I was giving an extreme example.
For him to get out to 600yds he only needs something in the 20 MOA up travel (or less) range.