What modern wheel and tire size could be replaced from 32-630 ( 27 x 1 ¼ ) wheels
After measuring the outside diameter of my ETRTO 630 sized rim and tire with a modern ETRTO-622 sized tyre, (ie a "700c") I notice they have a slight difference which my fork and frame can tolerate.  

The 622 rim is 8 mm smaller diameter (4mm smaller radius) than a 630 rim and is a good fit.   So therefore I will go with a more modern 700c wheelset.

Thank you for those who have comment and helped me decide better.