I'm glad to hear the .5 mil needle is quieter with old vinyl.
That's exactly what I am hoping for.
I figure the damage that is done to old records is mostly at the top of the groove, where the record may get rubbed by fingers and dusty record sleeve and needle scratches.
The playing damage happens wherever the stylus contacts the groove. The larger the stylus, the higher up on the sides of the groove it will cause damage. I think the most common size for the past few decades has been the 0.7 mil or ellipticals that are 0.3 x 0.7 or 0.4 x 0.7. Audiophiles may have been more likely to use 0.2 x 0.7 ellipticals. But most of the records I'm finding in thrift stores probably weren't owned by audiophiles.
Since 0.5 mil styli have been rare for decades (I think), most of the playing damage is higher up on the walls of the groove, so maybe the 0.5 stylus can play the groove wall that hasn't been touched.
Some folks have said that all the dirt gathers at the bottom of the groove and the smaller stylus will hit that dirt and cause more noise. That may be, but I have an ultrasonic record cleaning machine, so if that dirt is there, I hope I can clean it out before play.