Digital BW, The Print

I have access to about 200 glass negatives, many of which are 5 x 7 
and some of which are cut in half on the long side at 4 x 5 size.  I 
have an Epson 2450 scanner. Although it comes with a 4x5 film scanner, 
the 4x5 glass negative does not fit in it, and I have no carrier for 
the 5x7.

Has anyone ever scanned these negatives?  Any suggestions?  Should I 
try to make a cardboard holder?

Can the glass set right on the glass on the scanner?  Emulsion side 
up?  Down?

Any resolution suggestions.

Nancy