A Mag Spark came with a gun I purchased from the Forum Classified not that long ago. Although it worked, I have enough trouble dropping things like percussion caps, let alone small pieces like a primer firing pin assembly component, that I wouldn’t consider using one in hunting situations without spares for the droppable items. I carry extra caps (or flints) when hunting. Drop the Mag Spark firing pin assembly into the leaves, mud or snow, and you are potentially done without a spare.
Another thing to consider, while percussion caps are difficult to find today, 209 primers disappeared for a stint not that long ago. If you are committing to using primers, suggest a thousand minimum, unless you don’t shoot much. Also would suggest Federal brand based on experience for consistency. I know I can go through a lot of caps when I am shooting percussion. Not sure of my exact inventory, but have north of 10k. When I was actively shooting SASS I would go through 200 or more a month (2400 plus per year) for SASS alone. These components don’t seem to be getting any cheaper. Now is the time to buy, whatever it is that you are using.