Rajesh,
As I already said all those recommended parameters are not completely true, this decision depends on your database and the type of the database.
We DBAs are the whole and sole owners of all the parameters and values which we set 
Taking an example our saptools database should be 1-3 GB but we are extending when we receive 1105 Error 
similarly we are the responsable for our database which is our BABY
Coming to your question:
Option 5: is for aggressive garbage collection for the House Keeping, if your database has delete operations for concurrent operations, definitely go for 5, because it is very cost effective
Option 4 is more or less for the batch deletion on the DOL tables not much recommended for the normal delete because it is too costly 
Regards
Kiran Kumar A
SAP