How can I create a capped collection by storageSize instead of dataSize?

Question

Running MongoDB 4.0.4 on Debian GNU/Linux 9 (stretch), with a collection capped in size to 2.9TB with unlimited number of documents with the WiredTiger engine.

{
    ...
    "size" : NumberLong(3113851252530), // <= ~2.9T
    "count" : 238059628,
    "avgObjSize" : 13080,
    "storageSize" : 863343902720.0, // <= ~804G
    "capped" : true,
    "max" : -1,
    "maxSize" : NumberLong(3113851291136), // <= 2.9T
    ...
}

So size reached the cap of 2.9T, I also started overwriting older documents. However I created the collection with storage size in mind, I couldn't care less about size of uncompressed data.

There's plenty of space left on disk (8TB). Also got the exact same behavior in a capped collection of 1M.

Can I cap a collection size by storageSize instead?