I think, if you want play 3 1/2 Disks Games, you will need any A500 REV 6 and external Floppy disk Unit.
But if you want use with WHDLOADd, i think the A600 are fine..
Now, i have many problems with any A2000 kicktart 2.0 with WDload Games and Demos.. then i am not sure if are the same with any A600
In the A1200 for me work everything fine, but the only thing is wich Acelerator Card you have, becouse with the 030s i haved problems, but with any 040, no problem..