Wow, the dents in the top of that quarter look familiar, I dealt with the same on my 69 RR.
Take it easy with the heat if you can help it. Try to "raise the dents" by reaching inside the trunk opening and pressing firmly against the back side of the dent with the dolly that fits the best. Then strike the top side with the hammer but strike off the dolly, do not strike directly on the dolly. If you hear a "ping" noise, you are DOING IT WRONG. Ping = stretch. You don't want to stretch the metal.
Strike off the dolly around the edge of the dent crater and raise the low areas with the dolly.
When you are done raising the dent with hammer/dolly test the area for oil canning. Push on it with the palm of your hand to simulate the inevitable (some chick is going to hop up on top of that quarter panel and sit on your car like she's in a country music video) You want the top of that quarter to be stout from the back corner of the window to the tail light bezel. If it oil cans, your glaze (filler) will likely pop or crack when wanna be taylor swift load tests it with her bony ***.
This is usually where i use the heat. Not to raise dents but to try and shrink the skin in an area that got stretched from a dent and now oil cans.
But go easy, that heat can be a road that's hard to come back from.
Good luck on the skins.
Prop mentioned that I put some pictures of my skin install in my project thread. I guess I did, I'm so damn slow on my project that I can't remember exactly what I did right now lol.