Don't know if my one experience preserving a tree stump might be of
help or not; it would at least protect the stump while you were finding
better advice.
 
I needed to dry a 15" diameter by 18" section of a birch tree trunk to
use as a raising stump.  (I'm a metalsmith.)  I left the bark on and
coated all exposed surfaces with paraffin, including broken areas of
the bark.  The stump then sat in the studio for over a year to dry
slowly.  Then I peeled it and scraped off the wax.  Worked like a
charm; no cracks.  It has been fully exposed to the atmosphere for over
15 years with no subsequent cracking.
 
Can't be of any help with the slicing, or the ultimate surface
treatment.
 
Colleen Lynch
St. John's, Newfoundland  Canada