Right now I am demoing the Z3TA+2 and I am enthusiastic. However I have some questions about the oscillator section. I would like to know how exactly the spread works. How many waveforms are spread and to what amount are they detuned? Also I wonder what the mode setting means.

spread is available in only multi mode in free and sync.  free mode starts waveforms where they left off and sync retriggers the waveforms.  multi modes turn an oscillator into 8 simultaneous oscillators which are spread by the value the knob is set to (unfortunately this displays as a % instead of cents). 

the rest of the oscillator modes are on pgs 21-22 of the user manual.