What size Hard Drive for A1200???

[amigakit]

For gaming 2GB hard disk will probably be adequate for you needs but a 4GB hard drive will certainly give you more room especially if you install SCUMMVM games later on!

If you go for more than 4Gb you will need Kickstart 3.1 ROMs, the SCSI device patches, the NSD patches and an updated FileSystem such as the free SFS.

[amigakit]

The 3.0 ROMs have a limited SCSI device.  To use the LoadV43Module (the SCSI device patch) you need Kickstart 3.1 ROMs

Alternatively if you have 3.0 ROMs you can use the third party commercial IDEFIX package which will also get around the limitations.