Just trying to plan ahead (rather than behind as usual).

In the timber work of my house, there are two repeated motifs. One is
three partly overlapping circles and the second is a shape a little
like a comma (or a curved teardrop) on its side. The circles tend to
go through the thickness of the wood but the commas are carved into
the surface to a depth of about 1/4 inch. Since I shall have to
replace some timbers with each motif in over the coming months (/
years!) it would be sensible to make up some jigs for the router so I
can cut them reproducibly and regularly in the new wood.

The overlapping circles should be quite simple but the comma has me a
little stumped: I seem to remember having a set of french curves when
I were a lad about the same shape and it could easily be that the
Victorian carpenters used something like that as a template.
Naturally, according to Sod's law, none of the french curves I've
found so far is the same, so I can't copy them. Since this motif
never goes full depth (at least not in any place where I want to take
it down) I can't really steal a bit from the building to make a jig.

I can't imagine ever getting a reasonable result either trying to draw
the comma or, if I did, trying to cut a good template along a drawn
line. I'm wondering if there's a way of using one of the originals in
situ as a mould, then using the moulded piece as a template to make a
jig. Has anyone ever com across/solved this one?