Have a NO 1 and NO 3 and both have been fitted with different caliber barrels and required the ejector to be changed or altered if you will. Douglas Barrel Co. has done this work and not a problem to do that. Your home is very long way from Douglas but altering the extractor to suit a caliber is not known to be a difficult job for a competent gun smith it would seem. Just a thought.
My experience is that one usually winds up ahead by selling (or keeping) the rifle to be modified and buying another in the caliber you want. The Ruger #1 has been made in a great many different chamberings, and unless your desire is for something really exotic, that might be the way to go.