Which Ruger No.1 model would most easily be converted to .333 Jeffrey Rimmed ?

The action is the same, except for the extractor, whether for 22 Hornet or 416 Rigby. Extractor, barrel, sights, and forend are the only differences between calibers and models. The extractor doesn't care if the cartridge is rimmed or rimless. You may have to change it, depending on what you start with.

Start with one of the style you want, then you will have less to change.

The .333 Jeffery Flanged is fantastic. .080" rim thickness I think. I haven't checked but what is bore diameter? The .338 Doesn't work I don't think. So barrel change will be required.