About the size, when mounting my GPT disk in ImDisk, i initally was manually filling the offset and the size.
Then I decided to fill in only the offset, leaving the "erroneous" size=4294967295.
Well ImDisk did not care much and mounted my partition fine.
Which is finally no surprise as ImDisk probably uses the size from the PBR.
Well, actually that would be the actual filesystem recognizer that accesses part of what IMDISK addresses anyway.
The thing that gets a drive letter is the "right size" because it is derived from the BPB of the PBR, but it is read there NOT by Imdisk, but rather from the filesystem driver.
IMDISK reads the size from the MBR.
If you try (in IMDISK) to format the "target" you won't get "good" results.
Try playing with the attached morethanafloppy images (try re-formatting from IMDISK the one and the other ).
Check the capacity of each, before and after the formatting in IMDISK.
Then try again, re-extracting the untouched images from the .zip, using the FORMAT command in a Cmd prompt .
P.S.: Sorry v77, cross-posting.