It works better than uae4arm when you have not much memory internally free as both the system and work drives can be on the SD card. It does involve making an extra System.hdf in a desktop tool and performing a copy <from> to <to> all clone after formatting the system disk as something named other than that e.g. Workbench so the copy works.
The directory for the Work directory can be copied off the Amiga Forever CD (which you own), and placed in the folder <StorageDevice>/Android/data/atua.anddev.uae4all2/files along with the System.hdf as the app only allows one of each and boot from one. It also seems to not allow some combinations, and a bare file system on the Work is better than the otherway round.
If you get the ROMs too from the CD, and place them in there, you get a purple boot screen, for some reason it needs a app emulation restart to use the disks in my configuration. The mouse is horrible, and so a little USB mini keyboard and trackpad combo is essential. You kind of have to have a bit of font imagination until you set the screen mode (which also needs a shutdown and restart).