Reversing macro lens doesn't help.  Reversing a 28 mm wide angle lens,
which is relatively inexpensive will get you a field of about 10 to 3
mm if you use a flash quite close to the lens distance. 10 mm with 150
mm extension between camera and lens and 3 mm with 250 mm extension.

If you have the shell in good focus (done with natural light and lens
wide open under lamp light and close to F16 for the photo) the photo
field of 3 mm wide should allow a graphic of 1.5 or 2 mm wide with good
definition.  You do need to buy an adapter to make the reversed lens
match the camera.

I don't agree that the camera body is on no importance.  It should be
SLR to allow you to see through the viewfinder what the camere sees
through the lens.  It should allow automatic control of the flash,
preferably with two flashes connected to the camera shoe rather than a
slaved flash that is started when it sees light from the primary flash.
 You manually set the F stop, the camera sets the time by controlling
the flash shutoff.  The camera body sets the way the camera knows that
adaquate light has been received when it cuts off the flash.  This can
be a central point on most cameras, or a number of options on more
expensive cameras.  You can get more professional results with white
light from a lamp, but if you take a lot of pictures, you save time by
using flash, and the results are automatic and quick.  With light from a
lamp, using too little light results in long exposures and distortion of
color and exposure.  A flash gives very bright light and exposes the
shell to high heat for a much shorter time, but is more expensive.


--
                     Aloha from Wesley M. Thorsson
Editor of Internet Hawaiian Shell News, a monthly Internet Publication
           122 Waialeale St, Honolulu, HI  96825-2020,  U.S.A
       http://www.hits.net/~hsn                 [log in to unmask]