Regarding the 720k disks. That's the capacity if formatted to PC format. Amiga can store 11 sectors per track instead of 9 so it can hold 880k if formatted for Amiga. A plain PC needs a better floppy drive controller to read or write Amiga formatted disks so you'd be better off getting the Workbench disks which come with CrossDOS which will let you read PC formatted disks. You will need to use WinZip or LhA to compress the .ADF to 720k to do the transfer.
When you get the chance, you'll probably want to get a 2.5 inch hard drive and 3.1 kickstart ROM for your A600 if you want to run newer software on it but if you're content with using your PC for browsing the internet and playing multimedia files (which would also require you to get an accelerator board which are rare for A600) then stick with Workbench 2.1 . The only other advantage to Workbench 3.9 is that you can use hard drives that are larger than 4 gigs. You may be able to do this with IDEFix software also. If and when you get a hard drive make sure your boot partition is less than 2 gigs so that it won't get corrupted and overwritten before the new IDE drivers load in.
