8 ball, like vegabomb said.
As for 10 vs 8 ball… I wouldn’t say that either is inherently better. I feel like 10 ball bearings, such as the OD 10 ball or YYJ Seed bearing spin a little smoother than other flat 8 ball alternative, but they spin just as smooth as profiled 8 ball bearings.
It could be that it’s the higher build quality of 10 ball bearings that make them smoother, and not the two extra balls. It’s difficult to say. However, you don’t need 10 balls for quality and 8 balls don’t mean bad quality.
Also, if you do decide to go with a ceramic konkave, protect your investment by keeping it properly lubed. A lubed bearing is a reliable and quite bearing. The performance increase of running a bearing dry is negligible and not worth the rapidly increased time-to-failure. Any thin yoyo lube will work. They’re 90% the same anyways.
I’m not sure if you’ve ever learned how to properly lube a bearing, but there are tons of guides in the mods and maintenance section of the forums.