Gap under headliner

Anyone know the gap size between the roof sheet metal and the headliner? I’m asking because I plan to install dynamat extreme and then dynaliner on top and the dynaliner comes in 1/8”, 1/4” and 1/2” and I don’t want to go too thick and cause issues reattaching the headliner. If it’s unknown I’ll just go with 1/8”. Thanks !!

 

There at least a one inch gap between the headliner and roof skin. Several people have insulated the roof (myself included) and there’s plenty of room for two to three layer of material there.
This thread is for second gens but some people have commented on their experiences with third gens closer to the end.
https://www.tacomaworld.com/threads/removing-your-headliner-and-insulating-sound-deadening.394469/

 

So go to town with 1/2” dynaliner?