I found these pictures on the Dinitrol site and thought it may be of use to people as a guide... it shows where the Dinitrol people think their product should be applied to the insides of an Etype - including where to drill new holes etc..
I am voicing no comment on how appropriate it is - just sharing the info...
Naturally there are other products out there that provide protection.
But for rust protection you need to overcome this...