First
respectfully MCA and many of us use the term "sound deadener" for the product applied at the factory and "undercoating" for the stuff that the dealer changed extra for and applied every where. Reduces confusion
Typically the cowl or firewall section visible in the front wheel wells received a pretty good coat (seam sealer was already applied early in the assembly - front wheel well sound deadener was one of the last things done to the cars)
This application included typically, the splash shield and the rubber seal
The minimum was applied to the rear inner fender from the bottom of the firewall to inner meeting point or foot box upward and forward - to about where the front spring cover was bolted at the top
The minimum application then started again from the top of the spring cover at the forward edge to the bottom forward edge of the front inner apron. Including a pass often to the back of the front splash shield and rubber seal.
It was not unusual from the ones I've seen for the worker to make a pass with the application wand along the bottom of the fender - sometimes including the edge of the inner apron lip.
All of this application could be a little or allot of product depending on the day, the worker, how tall or young they were. It seems that most of the time IMHO the side match, in that if it was a heavy application both side were heavy
Will look for a couple of examples and try and post tomorrow - been a busy day
