It's worked perfectly so far. I got these:

Adapter:
https://www.amazon.com/gp/product/B0036DDXUM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Card:
https://www.amazon.com/gp/product/B00NUB2TWI/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

BigDisk Builder V6 worked fine, applying the player worked fine, applying the latest Hijack worked fine. I was able to copy all of the FIDs, all of the VAR folder, and the dynamic data partition, all over from the old drive to the new drive, from the empeg shell prompt. Everything works as expected so far, and I got no error messages during the copying process, as long as I had the master/slave order set so that the old drive was slave, and the new drive was master.

What I have not done yet: I have not tried a synch with emplode yet. I have a somewhat large set of tunes to add (several albums' worth), and I'll do that some time when I get a chance, and if that goes smoothly then I'll consider it done.

A couple notes about that CF adapter:
- It doesn't have a master/slave jumper. Instead, you plug the CF card into the adapter's Slave Slot or the adapter's Master Slot to switch it back and forth.
- I don't trust the CF card's ability to stay in the slot with the empeg riding in a bumpy car. It's only held in by the friction of the pins themselves, there's no clamp mechanism. So I put a piece of strong tape across the top to keep it parked in the slot.

Thanks so much for your help!