Kevin, it doesn't sound like you're as interested in a lift as you are in improving the ride. So, first I would try and restore any suppleness that might have been lost due to age and corrosion. Then, having done all you can, you can decide your best course. Yes, cleaning and lubing the shackles is good. But what I would do first is break free any interleaf corrosion/ that might be fusing the leafs together. Unweigh the springs. Then, using a big screwdriver, pry the outer edge of each leaf down and spray between them using a generous amount of penetrating oil. WD-40 will even do. Don't pinch the ant-friction pads in the process (if you've got them). You're just cleaning, lubing and ruling out one of the causes of your harsh ride.
Also, a while back I was using KYB gas shocks. ...way too stiff.
Also, a while back I was using KYB gas shocks. ...way too stiff.