Grade 100 balls can be slightly heavier by approx 2 grams due to their nature of slightly denser steel in order to get more precision.
So maybe expect slightly slower game play with those balls.
Pinballs should be as close as you can get to 2.75 oz or 80 grams.
Im happy enough with the grade 500, but I throw them away regularly to protect my playfield. They are precise enough for a wooden playfield,
I also polish them if I have the time, so they are always pretty much "super shiney".
But really its all splitting hairs, use whatever ball you like, just change them every time you wax at about 400 plays.
That said, I still prefer high carbon on magnet games. The seem to work better for me.
If you have a lot of games as I do, and they get played often, ball replacement can get expensive unless you buy in bulk.
I store them in packs of 25 with my vacuum bagger so they dont rust.