Doepfer

I think you need a ringmod.  Do the 110's have a FM jack?  Maybe at
least one better oscillator like Doepfer 111, or PlanB Model 15, or
Analogue Systems 95.  You can get some low harmonic sounds using FM or
a ringmod. Do the 110's have sync?  I don't own a 111 or 110, so I
don't know, but sync would help fatten up your sound too.

An animated square wave width sounds pretty fat, I don't know if
you've tried that.

Have any samples of how fat a sound you've gotten, and maybe people
could use that as a starting point/frame of reference?