I scan many types of paper including pulp. If you are concerned about bleed-through, place a black or gray sheet or book behind the paper if it happens to have any drawing on the other side. I also own a Brother MFC J6920 DW A3/Tabloid (11in x 17in) scanner.
It's inexpensive at $299 or less and saves having to "stitch" oversized artwork.
You should just pick paper based on the media you use, but quality material = quality results. If there is any texture in the paper your scanner is picking up you can use a Levels Adjustment layer in Photoshop. See A Simple Way to Get Better Scans by Wayne Fulton. He offers easy to follow advice.
Sometimes I place a towel over the scanner to keep outside light from interfering with the scan, and place a little weight (a book for example) to keep the paper flat against the glass.
Speaking of which, I clean the glass before scans to remove any dust specks that happens to get on the glass.
I think that should get you started with a minimum of fuss.
Gene