Chris, you mention edge-gluing the two pieces of veneer together, and then gluing it to the substrate. If you do it in that order, you have to be very fussy about the edge-gluing step. If the two pieces of veneer get a little out of alignment in spots, when you put the glued-up piece down on the substrate, there will be little voids along the glue line. A better way to go, IMHO, is to just veneer-tape the two pieces together, and glue that to the substrate. You're sure to get a nice thin glue line between the veneer and substrate.