DLNAME is short for Dynamic Link Name. It would be similar to you setting a windows short cut link in My Docs to the base location of your assemblies.
I am not sure of your situation but for the most part DLNAME could be a bit of overkill. I snapped a few images and placed them in the attached doc file. The DLNAME structure helped out with keeping the catalogs in multiple business units as the server paths were different. You could achieve similar results with Windows short cut links to the My Document folder to get the designer to the end location faster.
#3 is a big time saver. Custom menus are added at the assembly level for template instantiating and macros used at the assembly level only. Likewise, UDF and macros for PD (Part Design)/GSD (Generative Shape Design) workbenches.
Regards,
Derek
Win XP64
R20SP7/21SP5, 3DVIA Composer 2013, ST R20
Dell T7400 16GB Ram
Quadro FX 4800 - 1.5GB