@causerino Hi!
I know it’s been a while, but I’ve done this as well.
Make sure the SparklineIDs name corresponds with the slug name provided by CoinMarketCaps API.
For example, I wanted to add Elrond’s eGLD.
The ID for this token is 6892, while the slug is elrond-egld. As this includes a hyphen symbol, it needs to be surrounded by quote marks.
So my addition looks like this:
I also made 2 symbols, which are not required but look pretty.