yeah just keep piling it on. Then add some nice shag carpet for the ultimate in sound deadening and fashion! Purple or tiger stripe works best.
If its noise you are trying to suppress i had some interesting revelations when i did my blazer a few years ago. Might be of help to you. this is aside from the normal coating of the passenger compartment carpet kit area.
Areas that made a BIG difference in sound:
Rear fender wells. It is just a single sheet of metal and allows a lot of road noise in. I covered mine in the factory sound mat then rubber mat over that.
Firewall, the whole thing up to the windshield. You have to remove the dash, but i was very pleased with the effort once i was finished. I used Duramat for this portion on the inside and had the engine bay side sprayed with LineX.
Door skins. I had mine sprayed with LineX on the inside of the doors and that made more of a difference than i thought it would.
Underside of hood. Your hood is nothing more than a sheet metal drum and it excels at this. I used sections of Duramat and cut them to fit in the areas with no reinforcement. I was going to do a second layer that covered the bars as well, but cost and time kept me from doing this. the noise suppression was impressive and i really liked it. However over time the duramat has peeled off due to heat and gravity and i have not bothered to put it back on. I figure its a blazer, not a lexus. One thing to remember is your springs might not hold up the weight of the hood if you slap a bunch of weight on it.
I am going to be building a 1009 in the coming weeks for my girlfriend and will LineX the underside of the hood so we will see how that works.
A headliner will also help with the noise. I put a thick one in my civvy K5 and loved it. Unfortunately it was cheap and promptly fell out after the first winter.
I chose LineX over duramat for a lot of areas because of the ease of installation and cost. the place down the street from me has done a few trucks of mine and they are ok with me bringing a part by for them to coat for a few bucks on their next job. Duramat works better at killing sound though, so YMMV.