I have a HobbyCNC board, so my results might be slightly different than yours. I used option #2, no resistor, just hook the probe between the input and ground. My board has a built-in 10K pullup resistor. If your board does not have a built-in pullup resistor and you go with option #1, the resistor should probably be between 1K and 10K. 56 ohms seems way too strong.
I bought a cheap CNC touch plate off Ebay. There is nothing complex about it, so the $4 cheap ones work just fine. I stuck a rare earth magnet into the clip and just touch it to my router bit.