The way I did it on my A600 was the following:
- Run UAE with adding the CF card as Hard Disk (My Laptop had CF reader)
- Run HDToolbox from WB (I used 3.1 WB)
- Partition and Format the CF Card - Don't forget to make it Bootable
- CF Disk is ready to be used
I guess the following steps would be the following:
- Copy the System.zip (Of the distribution of ClassicWB of your choice) to the CF from WB
- Make the Disk from the ADF that ClassicWB provides and boot it, or just boot the ADF through UAE's DF0:
- Use your Original WB 3.1 disk or ADF for ClassicWB to continue
- blah blah blah
- Your ClassicWB on CF is ready
- You take off the CF and put it inside the real A1200
Have fun
P.S. Don't forget that the CF cards have a limited read/write cycle life so booting every day from the CF and running intense reading/writing will make your CF card useless in some months...
Cheers