This is a good question - my season just ended was one of experimenting with some of these questions, having many "tweaks". I won't say that my butt has reached nirvana after a century, but it's okay. The only real issue I've had was something like the OP - a little more weight on the hands than was comfortable at times.
Long story short, I got a shorter stem so that reach was a little less, and this helped the most, because I was keeping my hands on the "corners" of the bars a lot instead of the hoods (I read in the drops fairly infrequently). I've also become extremely conscious of where I place my hands on the bars, and I've also stuffed a couple of pieces of Dr. Scholls pieces in my gloves as well. I never had any numbness - just a few episodes where hands fely "bruised". In my experience, the "fix" is either a shorter reach (e.g., shorter stem) or raising the bars, typically with a stem with a steeper angle since most road bikes with threadless headsets have a more or less "fixed" steerer height.
I am looking at building up a frame over the winter, so another approach that I'm working is frame geometry with a shorter top tube and/or longer head tube. It's difficult to get a sense of how big a difference this will make in the end -- right now it's just a spreadsheet of numbers for different frames compared to my current ride.
Curious if others have gone this route and what the results were...