I definitely didn't add the SCSI interface lol. I just hacked in some calls to MAME's chdman, wrote a bare-bones iso reading routine, and started a scsi simulation (just to make warzard work... it's not quite there yet, but it's a start).
As for the wait, no. Since i'm not properly emulating the scsi, you will only have to wait for the chd to decompress (which takes maybe 10-25 seconds).