Interesting question. Where are you getting your pig sinew? Most modern butcher shops just scrap the "silver skin" on the back.
The bigger the animal and the longer the sinew the easier it is to use. I like Elk sinew because I can get pieces up to 12"-18" long. Deer sinew is a lot smaller. If the hog sinew is a good length it might be a good thing.
I suppose you could use rabbit sinew but it might take a whole rabbit to do one arrow.
