4 cm across? I say use birdshot on the swarms. Just watch your backdrop.
Heh, lucky you. I bought a c64 a couple years earlier and only the third one lasted more than a couple of weeks. The other 2 had to be returned for a blown power supply and a defective keyboard.
Now admittedly that last one lasted at least 12 years or so. For all I know it may still work, but I had to get rid of it.
Memory fault -- brain fried