At the request of PeteW I'm posting some details of the ISOMA centring microscope that I'm using to help me set the correct tool heights on this lathe.
I've been assured that setting height using VDI30 tools is easy, as the top surface of tools is in alignment with the tip height, and the upper surface of the tool holder is on centre line. However in my experience neither of these theories is correct by quite a distance

Now on a manual lathe I'm antediluvian, and use the 'trap a 6" ruler 'twixt tip and work and set to vertical' - works for me, but in this machine firstly it's all inside a sealed enclosure, secondly the X axis is slanting at a steep angle, and thirdly the tool is held upside down as it is on the far side of the work from the operator

Hence experimenting with the ISOMA, which I've had for decades but have rarely used.
I'm afraid the 'through 'scope' shots are pretty dim - but that's the way it is
