I’m in the process of using Eduard PE zim for my Panther. I have it most applied, and it has been relatively easy, although a tad tedious. I have been applying the PE zim prior to major assembly.
For gluing it down, I taped the pieces in place, and then ran CA glue along the edges, letting it flow under from capillary action. I then peeled of the tape and finished going around the edges. To get it stuck in the center areas of large pieces, I pre-drilled some holes which let me glue from the back, doing, in effect, the CA glue equivalent of a plug weld.
The biggest gotcha that I have encountered is the make certain that the PE is really flat against the surface when gluing. You don’t want it to form a gap, otherwise you run a strong risk of the glue filling in a bit and leaving the PE off the surface of the underlying plastic in the areas around the glue. If this happens, you run the risk of bending the PE into the void, leaving a slight folded outline of the glued area. The happened to me in one area, fortuitously in an area on the lower front hull, that I intended to damage anyway. My wee little mistake turned into a happy accident as I investigated ways to make the zim look damaged.
To simulate damage, I found that my dremel fitted with a tiny burr is wonderful. However, with dremelling, there are a few things to keep in mind. Obviously wear eye protection, and watch your fingers. When grinding near the edge of a piece of zim, you want to go at it from a side such that the burr’s cutting edge is rotating off the plate rather than coming onto it, other wise you run the risk of catching the edge and peeling up a section. Along similar lines, you also want to angle the burr in such a way the burr’s edges are not parallel to the zim pattern, other wise you run the risk of the burr’s teeth locking with the zim as though it were a rack and pinion gear setup, again peeling back the zim.
In addition to simulating damage, I also found the dremel handy for knocking down the edges of the plates a tad, just so that they wouldn’t look so much like the edges of a metal plate, but would hopefully look a little more natural. I added bits of putty, here and ther on the edges, to again to a better job of transitioning from PE zim to bare plastic.

Here’s the front with a bit a damge done to it. I still need to do a bit of blending with putty.

Here’s the rear of the hull, with the zim finished and blended with putty on the edges.
So far, so good.
Andy