I added a very thin 2-bladed alox Victorinox SAK to my Ritter Kit in addition to the scalpel blade. I think this was the Pocket Pal but in red alox rather than plastic. The alox is quite a bit thinner than the plastic scaled model.

Any decent univerisity bookstore should have plastic or metal scapel handles. The plastic ones could easily be trimmed to fit the pouch and weigh almost nothing. Adding another scalpel blade would also be a good idea.