How to adjust dippers
First, let me say this: It never bothered me that people say the Lee scoops throw a little less powder than the chart says. I ignore what the chart says. I determine what the scoop throws by actually measuring what it does. And I do this at every loading session whether using a dipper or a measure.
If you want to adjust the amount of powder a dipper throws, simply reduce its volume by putting something in the bottom of the scoop. (Wood glue, rubber cement, hard candle wax, a plug of paper mache, anything that will take up a little space and won't "grab" the powder or contaminate it.)
Get a dipper that throws a bit too much powder, a drill bit that just fits inside the dipper, a small brush, some wood glue. Dribble some into the bottom of a dipper that is too large. Let it harden and measure how much the dipper provides. If it is still too much, add a little more glue. Once it is too little, take the drill bit and (holding it in your hand) carve out some of the glue. Keep at it (trial and error, also known as cut and fit, is not all that tedious) until the dipper drops the proper amount. This is how we adjust powder measures, isn't it?
Alternative is to get a machine screw/bolt that fills the inner diameter of the dipper you wish to adjust. Drill a (slightly undersized) hole straight through the bottom of the dipper and thread the bolt into the hole. The bottom of the dipper can be adjusted up and down by turning the screw/bolt. It you used a hex head bolt, you have to do this from the bottom. If you used a screw with a round head, you could do it from either direction.