Don't recommend trying to widen the fork - that bike is a bit too vintage, rare and unusual to go doing frame modifications. Personal taste is that I'd be working on putting it back together in 'original' (either catalog or as-found) once I'd cleaned all the individual components.
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Syke
“No one in this world, so far as I know — and I have searched the records for years, and employed agents to help me — has ever lost money by underestimating the intelligence of the great masses of the plain people. Nor has anyone ever lost public office thereby.”
H.L. Mencken, (1926)