With some spare parts you can build a pretty accurate probing sensor yourself. This sensor can probe against every material and has quite a large probing stroke which gives you plenty of room between nozzle and bed.
In my case GCode M48 ;” Z-Probe Repeatability Test” returns the following:
Mean: 0.002250 Min: 0.000 Max: 0.008 Range: 0.008
Standard Deviation: 0.002359
That is more than good enough for accurate auto leveling. Check out a short video showing the sensor in action.
You need:
1x Micro Servo (e.g. TowerPro SG90)
Carbon/Fiber Rod (3mm outer diameter, Length about 35mm) for probing
Optical Endstop (standard reprap) for measuring
2x: M3x16 screws, nuts and washer to secure probe against DistanceBridge.stl
2x self cutting screws(2x8) for mounting the servo against the base
1x self cutting  screw(2x5) to secure the probe guide (it’s a snap fit, you might not need this one)
M3 mounting screws to attach the probe to your hotend
Disclaimer: installing & configuring the probe precisely and with caution is…