Diameter (Di): 8 mm
Thickness (S): 3,05 mm
The total diameter is always Di + 2 mm (wall thickness = 1 mm).
The total height is always S + 3 mm.
The valve lash caps are needed to adjust the correct valve clearance when modify to a mechanical camshafts drive.
To determine the required thickness (S), you should mount the cylinder head to the engine block and then install the tappets together with the camshaft and measure the valve clearance.