Practica has M42x1 thread (pentax, Zenit etc), and the adapters you have are M42x0.75 (T-mount).
Try with this one:
https://www.ebay.com.au/itm/T2-M42-F...frcectupt=true
or this one:
https://www.ebay.com.au/itm/T2-T-Tel...gAAOSwj0NUd0lL
They will bot screw into Practica (M42x1) and your eyepiece adapter will fit into female M412x0.75.
In the meantime I wouldn't have problem to use 3d-printed part.