Hi Dana
Just keep the clasp with the box and any paperwork with a note where the necklace is.
I am so in favor of magnetic clasps. I think the half-round ones are the best and easiest to use.
I got some magnetic clasps from Bella I find extremely difficult to use. They are shaped like rice kind of and you have to slide them against each other to get them open. So be sure you get them to explain what kind of magnet shape before you buy. For Miss Miriam, I do think the pull apart clasps would be sufficient. Here is a gold filled from Artbeads:
LINK
Here is my personal favorite clasp
LINK 
It has an edge that catches and protects from pulling. You pull both ends toward you and it breaks open. It is so easy....the downside, sometimes the magnet comes loose ( This happens most often when undoing the clasp, so the other part of the magnet is still clinging to the other half.)and I have to super glue it.
And don't worry about iconoclasm over here! We are very good at it! Golly, I don't even use silk to string pearls any more, because of the way it stretches. All of the instructions on cleaning pearls are easy; it is the silk thread that makes it tricky.
I gave you Artbeads because they are fast and no postage is charged.