Re the mounts, I used one of these motor mount options (full version) - guessing you've already seen this anyway.... but yes, seemed to work for me so far, but the plywood version dug into the foam would also work just fine. I liked being able to use the stock mounts. If you use hotglue, expect it to fall out at the slightest bump on landing. Gorialla glue seems to work for me, but it has also allowed me to remove my mounts when I had a problem mounting. Add some other glue on the edges and I don't reckon it would move. Haven't given my TStar a real thrashing on the motors. Several flights so far.
Here's the link to the images: