Thanks for that. I'm not quite sure I'm willing to sink another $50 (the shipping is more than the item ) into this Quadra. It's a pretty rusted out hulk because of the battery bomb. I've already spent too much on it just to get a power supply & processor. We'll see how my poor 3D modeling skills do first.
I think I have his non-eBay contact information somewhere. So, you might be able to get in touch with him and see if he'd send it via USPS, and for a lower price, before shipping is added in.
I'm now fully up & running with the floppy drive. Thanks again to @phunguss for providing the measurements that got me where I needed to be. If anyone is interested in my design files, let me know and I'll upload them to GitHub. My design for the floppy drive sled probably won't work for everyone because I'm using a floppy drive that I had just lying around (not the original for this computer).
As a bonus, iterating the floppy drive sled until I got it just right finished off 6 filament spools that had hardly anything left. At least I was able to use them for something.