Dynomatting the 'vert floor?

Has anyone done this to minimize cabin drone?
The sound gets pretty tiresome when cruising along 1800-2200rpms.
I'm wondering if padding the trunk & rear seat area would make a significant difference?
How much dynomat would be needed?
Stuff is damned expensive.
 
I did that to mine using some insulating material that came in a roll from Lowe's hardware, all I did was cut it into sections and used 3m adhesive spray to glue it down. It made a noticable difference in sound reduction from road noise and exhaust drone.
 
ive been thinking about doing this to my 88 vert. the heat from the trany and exh. will cook your feet in the summer plus the sound is driving me nuts.
 
I used Peel N Seal from Lowes. Not something for the doors or roof, but it's held up well on the floor. It never stank. It worked fairly well. For better results you would need to double it up and there are better products for that like RAAMAT.