I installed classic on to a standard 1200 recently. I followed the instructions on the bloodwych site.
Installed into winuae using the hdf file and some workbench adf's.
Then zipped up the contents and made the boot floppy as said on the site.
Then copied the zip over using pcmcia cf adapter.
Booted the boot floppy i made and unzipped the .zip file onto the blank drive.
I bit fiddly to do the first time but once you have made it once its easy to reinstall.