Hello Marco, and welcome.
I've been reading your posts, but did you already know you can boot the A1200 using OCS/ECS? If you didn't, this is the way to:
Reboot the machine, hold in both mouse buttons, and you'll get in the Early-Startup screen.
Next click on "Display Opions" and you get a screen where you can set various options, like NTSC/PAL, but also the chipset type (Original - OCS, and Enhanced - ECS), choose whether you like and click "Use", back on the main screen select "Boot". Or you can also go to the Boot Options menu and disable CPU caches. If you do this, you have a better chance of old games working. Still not everything, but it's better than nothing.
And I would also like to add that I also recommend a CD-ROM-drive. I got myself one a few years ago together with a Squirrel-SCSI, which connects to the PCMCIA, was a bit expensive though, but in the end I'm happy I did spend it . :-)