Its hard, when even Ensign - who make the bloody things - don't know the difference between a 26x2 1/2 tyre and a 650x65 tyre. Although the measurements roughly equate, they use different size and shape of rim. In the day, there were warnings galore about not confusing the two...
Anyway, if anyone wants info on BE tyres click the "Home" button on this site (upper left) and type "beaded edge tyre" into the search box. EW discussions, in particular, are expansive.
Donn, what is wrong with the original rims? In my opinion, restoring a motorcycle is best done by keeping as many original bits as possible, and if they are too far gone replacing like for like.
Ron, my usual advice for EW is to replace the rims with 26x3, and fit 26x3 tyres. Safe, and an original catalogued option. 25x3 tyres really are obsolete, as are 650x65. EW rims for 25x3 are identical to 24x 2 1/4; fitting 24x2 1/4 tyres to original EW westwood rims is fine but not really good for riding.
Cheers
Leon