When I want to look at period details in high quality photos I look to the
Speedplay Museum
Go to the bikes in the years of interest.
leather, shellac, padded do not appear to be represented.
I have used very thin coats of clear shellac on cloth tape. It is unobtrusive and is used to prevent the tape moving. Yes, the tape was installed damp after immersion in water. The tape dries and tightens up. The clear shellac was to act as an insurance policy to limit rolled edges.
It has worked, and with use, the tape is acquiring a gentle change in tone to show my hand placements.
Also available were rubber grips (reproductions are available) and sleeves such as the ones made by Dare. I have not seen reproductions of the sleeves. I have installed a NOS set on one 1952 bike.
Have a good look at the bikes in the online Speedplay Museum, particularly the ones kept in as last raced condition.