Some input would be great here is i have tried both, and they seem to work, however i am hoping someone who has alot of experiance in PDM will be able to advise.
Use Parts and assemblies in there original "first" assemblies, and then any assemblies using these parts or sub assemblies then look at the first instance.
All parts and sub assemblies are located in Parts, and sub assembly banks. and both (or more) aseemblies would then Shortcut to the parts bank.
Its really a question of should the original part or assembly be stored within a assembly or as a stand alone part?