I was originally trying to get Fedora-on-a-stick working with a USB 3.0 stick w/ a 32GB Class 10 SD card.

The performance with a "standard" install was not acceptable and updates took WAAAAAYYYY too long. 

Since the performance using the live method with a compressed image was WAY better I was trying to find a way to use the live type install with overlay-fs (or an alternative) and then have a way to take all the deltas in the overlay-fs file and commit them back into the main image file on occasion, but the tools aren't really "there" yet and it was very cumbersome. 

I think M.2 + USB 3.0/3.1 is the way to go but it is a lot bigger than my tiny USB 3.0 w/ microSD card setup.

Thanks,
Richard