I found one reference to the Monroe OC 8820 in Dr Dobb’s Journal, May 1985, in a table of disk formats (as used by Disk Maker I). According to this, the format is Single Sided Double Density (SSDD), 96 tracks per inch, 306KB, if this is of any help.
(Download Dr. Dobb’s Journal, Vol.6, 1985, at http://6502.org/documents/publications/dr_dobbs_journal/dr_dobbs_journal_vol_06.pdf)
BTW, the manufacturing seems to be of outstanding quality: clean layout, no bodge wires, a self-contained CRT unit, quite impressive…
P.S.: A pretty good image of the outside of the machine, for reference: http://lettieri.iet.unipi.it:4322/hmr_new/include/controller/web/showSpecificDigitalContent.php?id=71