vsti,vsti3,au,aax,linux Music-Society presents DOREMI by Beatassist.eu

[bluesmoke]

How can I fine tune the oscillators?

... you may to be able to get very fine control with the mouse by dragging radially before adjusting:

Holding down [Ctrl] will make it even more precise.

If they are linear, try editing the 'knob###.txt' files in the folder below the .dll and change 'mouse_response vert' to 'mouse_response rotary'.

Attached are the Windows versions with the .txt files edited as suggested.

Testing here on Win10 in VSTHost x64 & x32, and in Mixbus 6: 
  the x32 plugin knobs are rotary, but [Ctrl] has no effect;
  the x64 VST2 knobs work as described in the initial post;
  the VST3 knobs don't work at all ...

I have no idea why I'm getting different results with each format, or what will happen in other hosts - but if anyone finds a combination that works for them, the ultra-fine control is well worth having.