how would you go about making refrigerator door shelves ?

I recently purchased a used Dometic RM 7401L absorption refrigerator for a good price and it works great. However it was missing the three door shelves. I've done a fair amount of internet searches, emails and phone calls with zero luck finding any in the U.S. they may be available in England. The door has little rectangular male pins for lack of a better description that allow the shelves to be adjusted for height. The main shelf is the bottom which normally holds beverages, the middle has less depth than the bottom and the top one from what I can tell is used for things like eggs or small items. So if you had to make some shelves how would you do it ? I find tons of Dometic shelves on the net that are 17 3/4 " wide but mine measure 15 3/4, can the shelves be cut/narrowed and successfully bridged in the middle ? Or do it on one end ? Open for any suggestions other than replace the fridge.