I'd choose the straight shank balls sized to about a .001" press fit and peen the ends over thoroughly after they're pressed in. If the old ones held for 70-something years, that system seems to work OK. Don't mess with success!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!