SAP PP operation and routing

Dear all,

I have some questions about operation and routing :

1.There are 9 operations: ABCD EFGH I. Operation ABCD is sequential operation and EFGH is sequential operation that can be done if EFGH finished or sometimes EFGH can be parallel with ABCD. ABCD and EFGH is branch operation of I. How do we maintain this routing?

2.There are 3 operations (ABC) for mixing that after ABC back to A frequently. ABC are tanks that need labor just to move liquid in each tank but the mixing operation in general needs machine. How can we maintain the labor in work center category and maintain in routing?

3.Is there function in SAP to fixed time in routing? How many quantity that processed in the operation still use 1 hour for example.

4.If there is a balance tank as operation /work center which have safety stock . If quantity below the safety stock, production team will release production order.. How can we maintain the utility of the balance tank and to maintain time in routing?

Thanks and regards

Anita A.