The way I look at it on our place is we are low fence, so at best all our culling is doing is population control.
In a controlled environment or hf property both bucks and does cary genetics for antlers, but the only ones that express what they carry are bucks. So manage both bucks and does for the numbers you want to carry and shoot the older does. As time moves on the does that are born will have more and more of the genes that the bucks your seeing have.
I disagree. Yes, deer travel, but if you take that spike out before he travels and passes his genes on, you're doing some good. I do like your doe tactics-as you and STX pointed out, over time the younger does should have more of the genetics you're after.
A lot will have to do with CC, if you haven't exceeded it, then culling really isn't doing much.
If you haven't exceeded CC, then what you're seeing is more a result of genetics than nutrition, and IMO it's more important to cull at that point because you've taken out that part of the equation.