Because of the recent update in DTools, you have to wait 30 seconds between SCSI drive operations. This is normally fine for every day use as you're likely playing a game for more than 30 seconds. However, when setting up games, this can be a nightmare!
EmVoy lets you manually mount the relevant game image and then setup to skip the mount/unmount operation in the main procedure. This allows you to boot the game - change settings, exit game (which svaes settings), reboot and tweak settings.
The menu should be self-explanatory. Set "Leave Disk Image Mounted" to True to skip the mount/unmount operation when booting games.