The main benefits to a CF card over a hard drive is that it is silent.
Look in the tutorial section of this forum and there is an excellent tutorial on installing a HD in a 1200 and partitioning and installing workbench which will work just as well for your 600.
Kickstart 3.1 and WB 3.9 can handle drives bigger than 4 gigs. Anything below that should be kept to less than 4. But, its an A600, so you don't need a huge HD.
You really should upgrade that thing to KS3.1. Amigakit has the ROM's.
