If you will search the forums for "lead ballast" I think you'll find what you're looking for.
In my case, one 20KW generator was permanently removed from the starboard side and a 1,000# capacity davit added to the port side by a PO. I found 750# of lead shot under the tail pipe at starboard transom. I also have some lead pigs running under the port muffler.
Through better weight distribution of tools and supplies, etc., I was able to remove 400# of the shot (I sold most of it to someone on this forum a while back). I moved the remaining 350# forward to the outside of the stringer at the back of the engine room. That's also a bit wider than the transom making less weight go farther.
What I have been avoiding is the obvious. I'd like to remove the lead from the port side, thereby, freeing up some of the lead shot on the starboard side. It's really hard to get to it all in a convertible.
What I did learn from the search was maybe I might redistribute some or all of the harvested lead forward. Since I run my most efficient (on plane) with the tabs full down and fwd tanks full, it stands to reason that extra weight (in the chain locker or ahead of the first transverse member) might help me out. I guess the proof is in the doing. You would know you've gone too far if the boat does better with less tab. And, being so far forward, it probably wouldn't take much weight. Only downside I see is it might make surfing a heavy following sea a little bit more hazardous.
What sayeth ye?