Pblack,
The glue line measurement is a horizontal measurement that shows how much wood would be left if you were to remove wood from the inside and outside of the vessel until you meet the points where the above and below segment touch glue. Your desired wall thickness must be able to fit within this measurementWhen you take the slope of the wall profile at that elevation.
The way I approach wall thickness is to begin by making a wall profile with a pleasing inside and outside wall profile in 3D Design Pro. I then transfer it to Woodturner PRO with my intended height and click the profileSNAP button. I then turn on the glue line indication and look to see the measurement at the elevation where the wall is vertical. If it is more or less than desired I have two choices. If I plan to make this project again, I switch back to 3D Design Pro, adjust the inside our outside points and the repeat the transfer and profilesnap. I then save my 3D Design Pro design to a new file.
But if I don't plan on repeating this project, just make your adjustments in Woodturner PRO. The easiest way to do this is to select all (or most) of the segmented rows by double clicking the lowest row and the shift-clicking the top row. Click your left or right arrow to adjust the diameters of the selected row. You can do this either uniformly or proportionally and for an explanation of this, click the Software Tutorials category of the forum and watch the video on changing properties on multiple rows.
Please let me know if you have any additional questions.
Lloyd