I used the baking procedure on my first tail light today. I had a bunch of dirt/buildup inside the lens from the car sitting for so long in the 2nd owners driveway.
220F until preheated, then 8m to start on a cookie tray with parchment paper down, plastic side (with painters tape) down.
Then I worked slowly using a plastic dash removal tool loosening up the large end of the light as noted in the original post. Once the glue started to cool a little bit, maybe 1-2m of loosening/prying, I would put it back into the oven for 3 minutes, then repeat. After being gentle my 3rd cooking allowed me to start loosening up the big end. It probably took me 8 heat cycles in the oven until it started to really come apart.
After that I popped out the clear part inside the red lens, the clear part over center of the light and a little clear part on the end.
Then I cleaned everything really well, reassembled and set the red lens on the back piece without any pressure on them. Just heating up the glue to get pressed together. I did one 8m cycle for the initial press, then 4m just to get the last couple of edges pressed flush, again at 220F.
Not sure if it shows up well, but what a huge difference. Really happy with how it all turned out. Yes a stick is currently holding up my trunk
(struts are part of the winter build).