I don't know abt the post question what u had asked. But i know for the second one that REUSE option usage in Intrapartion TDQ.
The answer is already u may know that once if u read a record from TDQ it will be removed logically from memory but not Physcially. So, Due to this the memory will be wasted. To avoid this REUSE option is used tin INtrapartation TDQ.