I am about finished thinsulating my low roof 118. I have just a little left over and was pondering insulating the headliner above the drivers and passenger seats. I have seen the posts of folks doing that to the tall vans but none for the low roofs. I haven't undone the buttons to take a look at what's in there. From pushing on the headliner from below it feels like the headliner is thick, maybe already some insulation. Was wondering if it is worth the effort on a low roof. Anyone do this to low roof? Hate to pop the buttons and find it is already insulated or there's not enough room for the thinsulate. thanks.