I used Mastercoats metal prep and rust remover, then 2 coats of Mastercoat rust sealer. I rolled on the sealer and the surface looked great. I then put on Rustoleum black topcoat and that didn't lay nearly as nice as the mastercoat product line.
The next step is to apply heat/noise cancelling sheets to the entire floor, ceiling and trunk, I chose MAT66 80 mil. These pads are a butyl product covered with a foil top side that has square shaped dimples in it so that once you get the product layed in place you use a hand roller applying pressure so that the dimples lay flat, then your done..
Entire area behind the dash was treated for rust then topcoated.
I may build a sound barrier on the wall between the trunk and back seat but for now it will be left as is.
Prior to painting on rust preventer/sealer all seams were treated with 3M seam sealer
MAT66 sound deadening installed
ceiling of car was in great shape only had surface rust.