Engraving setup issues

I have created a couple of designs using v-carve and imported the g-code into easel with no problem. The setup and carving, it’s smooth.
My setup challenge arose when I tried to engrave using the diamond drag bit. I couldn’t use the z-probe, it doesn’t detect the diamond, i don’t know if it’s user error, so I chose to do it manually.
When used manually after the setup it tells me that needs to raise the bit and when I hit engrave, it does it, but the bit it’s at around 1/16” higher than the material. Later I chose again manual, but this time I selected last home position and did the same.
Lastly I selected the later, but this time I lowered the bit half way below my acrylic. It worked fine on the first test run, but on the second test it didn’t raised the bit enough and scratched the material at it returned home.
Any ideas on how to properly setup easel for diamond drag bits? Thx