Right, that's 16. There are also four more in the box from the torn down one. I think we'll have enough, assuming most are still good.
Hmm, what if we can use secondaries only or primaries only due to fitment issues? Out of 20 total, that leaves us with five sets of each type or ten secs and ten pris. Assuming one has gone bad in each batch, we're still good, if one engine can get away with secs and the other with pris.
Having lots of parts is great if you know what to do with them.