You need:
1 PC4-M10 fitting
2PC4-M6 fitting
They are designed to thread easily into the part with nothing else.
Link to CAD: https://cad.onshape.com/documents/9b921bb87603fcf385896afc/w/0aaf22fd1785b5446029f951/e/a52aed6eb0c9040fb6936e9c?renderMode=0&uiState=656fb4371e94b1216aa53c5e
The author remixed this model.
I had only 2 PC4-M6 fittings, so I modified it to use 1 PC4-M10 fitting and 2 PC4-M6