I am considering incorporating a drafting table into a set of built in
bookcases that I am getting ready to make. The first design question that
popped into my head was an odd one. Is the lip at the bottom of the
drafting table, the one that the triangles and such rest on, of any
particular dimension? Does it need to be a particular height above the
table or a particular thickness?

I have little experience with drafting tables, obviously, but I thought it
might be nice to have. I just bought my wife a mat cutting system (from Lee
Valley of course) for Christmas and thought it might be a good work surface
as well as my using it for drawing plans. My last project really taught me
the value of drawings of a project.

SteveP.