I'm an electronics noob so sorry if this is a dumb question. I am designing a very simple bipolar EMG probe. It consists of three copper electrodes on the bottom, each wired to a 3.5mm headphone jack on top. I'm planning to connect it to an off-the-shelf EMG amp like the [Grove EMG detector](https://www.seeedstudio.com/Grove-EMG-Detector-p-1737.html) or the [OYMotion Gravity EMG sensor.](https://www.dfrobot.com/product-1661.html) Here's a picture:  As you can see, the headphone jack's mounting holes go all the way through the entire board including the electrodes, reducing their contact area. The headphone jack [(PJ-621C)](https://atta.szlcsc.com/upload/public/pdf/source/20211105/FE62175CE755441EFCD415EDEBDCA661.pdf) has extremely tiny pins that do not extend below the component body so I don't see why it needs to penetrate 3 whole layers of fiberglass on this 4-layer board. Is it possible to stop drilling the holes before reaching the bottom layer? Even better, would that be possible on a 2-layer board with only a single sheet of fiberglass? I did find [this post](https://easyeda.com/forum/topic/How_to_create_blind_vias_-lb5ZTbsKE) about vias that said only through-holes were supported and blind vias were not, but that was only about vias and it's a 5-year-old post. Thank you