Is 8″ x 10″ really the smallest sheet paper I can feed to the Epson 3800 through the Rear Feed?
Not quite. You can feed in smaller sheets, but the trick is to set the page settings in your application to at least 8″ x 10″. For example, I recently wanted to print a few test patches on a strip of Moab Entrada Fine Art Natural paper that was 3 inches wide and 11 inches long (this originally came from trimming an 11″ x 17″ sheet down to 11″ x 14″). The actual image size in Photoshop was 2 inches wide and 4 inches long. So in Photoshop, I started with the 2″ x 4″ image and increased the canvas size to 3″ x 5″ while keeping the image centered and using a white background for the expanded canvas. This had the effect of placing a white border of half an inch all around the image. Next, I expanded the canvas to 8″ x 10″ while keeping the image in the top-left corner. This effectively made an 8″ x 10″ image with the actual image content in the top-left region of the page. I had no problem feeding the 3″ x 11″ strip of paper into the Rear Feed (short end first) and the image came out fine.
