Back in ‘75 I purchased an expensive Italian road racing bicycle. I've long since sold off the bike, but kept some of the components that I upgraded before then, such as the Universal Model 61 center pull brake calipers and levers. The gum rubber used in those brake lever hoods, same as the ‘gumwalls’ in tires of that era, deteriorated within a few years due to UV exposure. The levers are sturdy and stiff, with a lot of leverage and throw, perfect for cantilevers.
You can still purchase NOS(New Out of Stock) OEM hoods, for $50-85 USD on the specialty market, but why bother when in a few years they will look disgusting and need to be replaced? One solution is to design and print a top half hood, then wrapping with handlebar tap. I sacrificed an old 26"x1-3/8" inner tube to create a very tight cover (I would use a slightly larger tube--this was all I had to work with) that would hold the the printed top hood to the lever body, and cover up the up the side lever screw head and threaded end.
I was surprised at how comfortable the printed piece made the brakes levers. I hope this helps you keep a well made pair of vintage brake levers in use long after the the OEM gum rubber hoods are gone.
Included file formats: STL, STEP, FreeCAD
Resolution: 0.2 mm Infill: 15% Walls/Perimeters: 3 Support: Raft (to preserve curved bottom and sharp edges) Filament: PETG
I printed mine in PETG, more durable than PLA in the sun. ABS, ASA, Nylon would also work well. Surprisingly comfortable printed in a hard filament. Flexible filaments like TPU would give some cushioning.