[TR] Hood dzus fastener brackets - TR2/3

[Angelo Graham]

Hello LIst:
Looking at some finishing touches on my project and wondering what 
listers have used under the dzus fastener brackets. When I removed them, 
there was some form of petrified rubber underneath them.
Do you have to try to 'shim' the brackets to contact the dzus fastener, 
or is about 1/4" of material enough to do the job? Thought of using 
layers of old inner-tube rubber - material on hand.
Thanks in advance.
Angelo Graham