[Coco] OS-9 Level I v2.0 hard disk image how-to?

[Robert "Exile In Paradise" Murphey]

If I wanted to emulate a CoCo 2 with the 15 or 35MB Tandy hard disks,
how could I do it?

The OS9 Level 1 v2.0 addendum says the Tandy hard disks are:

15MB uses 6 heads, 306 cylinders, 345 tracks per inch, 32 sectors per
track and 128 pre-comp.

35MB uses 8 heads, 512 cylinders, 512 tracks per inch, 34 sectors per
track and 256 pre-comp.

The two options I know of up front to format a disk image are:
Toolshed os9 tool
MAME imgtool

MAME imgtool does not let me specify enough heads or cylinders, and my
suspicious is that the field is 8-bit anyway so the numbers given won't
work.

os9 let's me create an image with the same total logical sectors, but
the geometry doesn't match up and I don't know if that would stump the
driver or if I need to create a different device descripter.

So, I am reaching out to see if anyone has any tips on how to simulate
the original 15M or 35M hard disk on OS9 Level I v2.0 for a CoCo 2...
using emulators or hardware with the CoCoSDC attached.

-- 
Robert "Exile In Paradise" Murphey <exile at weylan-yutani.com>
Weylan-Yutani Corporation