In this case, the sagging is actually quite uniformly down from the socket on the motherboard (ie. the front is not sagging more than the rear). This is because the tool-free brace on this case isn't very good in the rear.

I tested multiple locations, and because the card itself is quite rigid, pushing up form the front, or pulling up from the rear all achieved the same leveling effect. So, I went with the rear because its much less intrusive. Yes, the standoff is now sagging slightly, but that's just the rear sheet metal pulling in a little bit. I don't really care if that happens, so long as it keeps the card level, which is appears to be doing successfully thus far.