Wet wood can be translucent when turned thin enough, and this property can be used to your advantage to help achieve a uniform wall thickness.
As wood drys it's cells shrink at different rates depending on their type orientation. If the walls of a turning are uniform it allows for uniform cell shrinkage throughout and enables the walls to move as they shrink. If the walls are too think or are of uneven thickness then the stresses in them when they attempt to shrink due to drying can cause them to split.
When using the property to your advantage you can put a light inside the turning and continue removing wood until you have a uniform glow. As you can see from the slightly darker section at the base I didn't do a perfect job with this one. Luckily, when the wood dries it looses this translucency (unless the wood is really thin) so no-one will know.
The piece is still, of course, sat in the shed waiting to be finished...