The Steebar designer is, I believe the same as the PSI.
Diameters for the PSI are as follows:
Clip end bushing 0.404
Nib end bushing 0.357
Center bushing small end 0.404
Center bushing large end 0.425
Optional sizing sleeve 0.565 (Diameter of upper barrel)
Tenon OD is 0.404.
I don't see them on any of the spreadsheets.