This is exactly the purpose for which FireWire Target Disk Mode exists, which is of no comfort to you when the tray-loader does not have FireWire. Next best then would have been to send a disk image of the install CD to the slot-loader (a 'net install') by ethernet, and install onto the slotloader from the image. But, with no OS on the slot-loader, even that is denied to you. Your natural adaptability may enable you to use the ATAPI tray-loading CD-ROM with your slot-loader, but none of us can see your setup or offer meaningful advice. Round about now you can, I am sure, see the virtue in replacing your slot-loader's CD-ROM drive, soon.
Best o' luck!
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