wireload model./custom wl creation

hi all, I use tsmc .13u library for pre layout synthesis. I have an option of selecting tsmc13_wl10,tsmc13_wl20,tsmc13_wl30,tsmc13_wl40,tsmc13_wl50 for this. TSMC didnt give any area range on which I can select the WL models. How do do select a model for my design. say my block area is

Also I wanted to know that whether we can create a custom wirelaod model without floorpalnning and PnR ..If yes how..

Also please tell me how good is DC for .13u, do u think physical compiler is essential for this process?

thanks John