Help with Torch-down sound deadener

I'm getting ready to finish out the inside of my 67 coupe. I have a sound deadening kit I purchased, along with the molded carpet, a few years ago.

The kit consists pre-cut roofing torchdown material made by Dibiten, sold under the name "Re-Pops". It's precut for the 67 floor and trunk. It looks like good stuff, and I'm pretty sure it's identical to the stuff my car had in it before I had the floors redone. Possibly factory original.

The problem is the Torch Down part. I possess, and know how to use a torch, but this job scares me (especially in the trunk area). Not sure I want to light a fire in my coupe.

So, I'm thinking maybe just corner-tacking the stuff with some liquid nails, and letting it mold itself to the floor over time with the natural floor heat.

OR, someone can tell me the torching part is easy-breezy, and necessary, and kinda walk me through the pitfalls, and I'll give it a go!

Seriously, any advice would be much appreciated.

Update: I actually got a hold of the RePops people. They said most people just throw it down and let it mold with the heat from the frame/floor. They said some people prefer to truly torch it down though.

I can understand why, because the Dibiten site explains that when applied to a roof application, the layer to be torched must be completely melted to for a water tight seal. I also talked to a Dibiten guy, and he said it must be torched to mold correctly, but it wasn't meant for what I'm doing, so... anyway, he didn't want to talk too much about it.

So I can see where there might be a problem with drainage (if water gets in somehow), if I don't torch it down.

I think I'll just try it without the torch first. I can always go back and torch it in.