The detune in the menu is meant for the Unison mode, which only takes 1 note or a chord as input, so not ideal for ur purpose.
Instead...
Stack the layers!
3 clean saws and maybe a square.
Add detune by adjusting fine tune (+/- 1-10) on each saw.
Add noise
Add a bit of slop
Apply LFO or ENV3 to the pitch for more detune
Adjust ADSR for brass og supersaw
Add chorus or verb to taste
Lastly create some full chords with lots of voices to use all of your 16 voices. Testing this made me wish i had the 16 model....