How To FULL DB EXPORT/IMPORT

Hello Tom,
How to do a Full DB exp and Import.

I do say
exp system/manager@xyz FULL=Y FILE=FULL.DMP

Then If I want to do a full Import to a new freshly created DB which only has the default schemas sys , system , etc.

1) Please correct me :-
I would need to pre-create all schemas /tablespaces for those schemas needed to import the user and then do a FULL import.

imp system/manager@abc FULL=Y FILE=FULL.DMP

2)Cant i just

imp system/manager@abc FULL=Y FILE=FULL.DMP and the users and tablespaces will be automatically created due to FULL option ?

3)Is the use of FULL exp/imp just to gather all schema files into one big file.

4) Suppose I need to exp import say only 10 schemas. What is better peroformance wise, do a fromuser touser comma seperated list of owners
or individually run 10 exp/imp commands. Are smaller individual files easier to handle/read by Oracle exp/imp utility?

Thanx