hi
I am interrested to. I didn’t fund any trial version. From what I saw it will cost 1000$Us for 300 ac?
Everybody around me is using OptiSurface, it seem to be the most popular, are there others?
Also, I mounted my prop valve on my blade.
The first test was not as good as I expected! The cut was wavy and the blade overshooting continuously.
It appear that there is a great delay from the real elevation measurement and the display/valve command. I think something like 0.2-0.3 second.
So reacting only on the distance from the cut line don’t work. the time the arduino think it reach the line it already overshot.
So my new arduino calculate the pwm value 10 times/sec and take in account the 3 last values to calculate the value.
Maybe it’s some PID? 
Now it works great:
The last versions are on Github, on development! This arduino is in the beta branch right now.