Setting parameters like PCTUSED when creating new tables in ORACLE 12 C
"Or will ORACLE automatically set these values efficiently"

Well, Oracle will set them to something by default ... probably not very "efficiently" though ;) For that, you're going to want to do a bit of research and groundwork on what YOU need.

As mentioned by Wernfried in comments, LOCALLY managed tablespaces are the way to go, and once you have those defined, specifying those options per table is wasted - Oracle will ignore them.

It's generally seen as better to setup certain types of Tablespaces for different types of tables used.  

Small, mostly read-only tables: 1 tablespace: set to small Extent sizes, and small/0 pctincrease.

Larger, highly volatile tables: another tablespace: larger extent sizes, larger pctincrease ..

etc.
You need to work out what your needs are, and what kinds of tables you have (and then what tablespaces/storage options you'll want).