I've already applied a best-guess based on the pics here, using the known size of the 68000 outline as the baseline to get the overall size. It *might just* fit fine without issues. The real concern is with the IDE connector bumping up against the underside of the disk drive or the 1000's massive disk drive mounting plate.
The mounting plate is a non-issue, you can dremmel that away - the thing is made of recycled battleship steel or something - you could cut way 8-90% of it and it would still be more than strong enough to suspend the floppy disk drive firmly.
Then there's the disk drive itself. The A1000 uses 3 different makes of drive mechanisms. All are different thicknesses, but all must align with the A1000's front drive slot opening.
Depending on which drive mechanism you have, you might be able to get away with cutting away at the drive's own external housing, and either raise the device high enough on socket extenders to clear the drive, or cut away enough of the drive underside to let the device clear that way.
Here's a 68040 board in one of my A1000s where I had to cut away both the drive mechanism's housing and the mounting plate:
Hopefully, with the Zeus it won't be quite that extreme.
What is really needed is a small 68000 socket-shifter - a device that moves the A1000's 68000 socket down about one inch. That would probably allow most A500 plug in accelerators to fit, including the two new ones being discussed here. I've seen a few people make their own - I even saw someone publish an egl pcb file for one a few years back, but nobody has ever actually produced a run of this adapter.