What Weight/Thickness MLV?

[boy&hisdogs]

I'm getting ready to do some sound deadening and insulation in my ext cab, the plan is a layer of off-brand butyl deadener, then a layer of reflectix (foil covered CCF bubbles) then MLV.

From what I can see, MLV comes in 3 common weights/thicknesses:
-1/2lb (1/16")
-1lb (1/8")
-2lb (1/4")

I'd bet I could probably get the thick stuff on the floor and back wall no problem, but how thick can you go in the doors and all the other tight spots?

For those of you who have done it, what weight/thickness did you use? How did it fit?

 

[TechNova]

I used this on the inside of the door skin, floor, rear panel, ceiling and inside the door instead of the vapor barrier.
Amazon.com: Noico Black 80 Mil 36 Sq Ft Car Sound Deadening, butyl automotive deadener restoration mat and Noise dampening insulation: Automotive
I did not use anything else.

 

[Bloke]

On the doors and back wall of the cab u can go as thick as you like but don't forget to factor in the carpet and padding it may come with along with the additional material your are adding, it maybe a tight fit.

I bought the cheaper carpet through RA, the one with no mass backing and the carpet looked very loose. I redid the interior to included the carpet again and bought the thicker one with mass backing added in some dynamat and it was tighter and plush but i used the 1/16. Maybe i could have used 1/8 with no problem but not sure of the 1/4 would have given me any issues.