Bud,
Just a couple of comments.
To get any .sea or .bin diskette to open ........ must be loaded on the MAC Classic II first.
StuffIt Expander (for a way of obtaining the 4.0.1 version for Mac, see above) will decode MacBinary (.bin) files, as well as BinHex (.hqx). A self-extracting archive (.sea), where the resource fork has not become damaged during transit, will expand automatically when double-clicked upon. If there is a problem, one can try to drag a StuffIt .sea file (there are other .sea files that may behave differently) onto the StuffIt Expander icon. Disk Copy 4.2 is only needed in order to open Disk Copy 4.2 type disk images, and is not required for the System 7.5.3 download.
I cannot unpack .smi yet. 7.5.3 first disk image has this and is needed to install the other 18 disk images.
When the nineteen .bin files have been decoded by StuffIt Expander (apparently, this is what you did already on the modern Mac), they (one. smi and eighteen .part) are to be placed in one common folder on the Classic II hard disk. As indicated earlier, then merely double-click on the .smi file. This should mount the total image (the 7.5.3 installer will be found inside).
Both the 7.5.3 (& 7.5.5) and 7.6.6 need their initial upgrade, i.e., 7.5 and 7.6 primary OS installed first.
I think you mean 7.6.1 (not 7.6.6). In that case it is true that 7.6 is needed (nothing earlier). The downloadable System 7.5.3 however will install and work as it is, provided that the Classic II hard disk has an appropriate bootable operating system. If necessary, a 7.5 startup floppy can be made from the aforementioned Network Access Disk 7.5 download.
A CD image can be transferred to the MAC Classic II (or whatever) by hooking up the MAC II 25 pin HD connection to another computer that that is connected to your Ethernet.
Apple supports SCSI Disk Mode (HD Target Mode) for certain PowerBook computers (equipped with an HDI-30 SCSI port). The PowerBook would then act as an external hard drive when connected to a desktop Mac (which has a DB-25 SCSI port). Special adapter cables have to be used for this.
Otherwise, a direct connection between two SCSI ports is not supported, and may be risky.
It is possible to remove a SCSI hard drive from one Macintosh computer, and then (via a different kind of cabling) connect it (externally or internally ) to another SCSI Mac.
Jan