I recently did a DIY where I affixed a 2mm thick garolite to an inexpensive spring steel build plate, and it worked out surprisingly well. At 2mm, it’s already quite rigid. I suppose you could get even more rigidity by going up in thickness.
As you can tell from the beginning of the thread, I was quite tentative about it. However, if you make it to the end of the thread, it turns out to be a cakewalk. i.e. very easy to do, and it seems to “just work”. One could argue (as explained in the thread), that it may even be better than Lightspeed, which I also just recently received, and which also work well, though not as thick.