When to start?

I've mentioned on the SOTCW Forum that we may have the possibility of more amphibious kit (more DUKWs) and that this brings the possibility of playing out the operation from the actual landing on the beaches.  My original assumption had been that we would start with the Commandos and Rangers ashore having overcome light local resistance.  

If we are to go from H-Hour itself we need to decide on things like:

• How many troops can the Germans have on the beaches?
• Is the Vietri coastal gun emplacement intact? - In reality there were no guns present 
• At what point can the allied naval forces begin to fire? - There was a ban on pre-landing bombardments as Clark wanted to preserve "tactical surprise".
  

What do you think?  Is it worth the extra effort?