This sounds like a relatively simple patch to set-up.
2 tone sources on same octave range, 2 sawtooth (possibly pulse on tone source number 2 ?), with tone source 2 very slightly detuned (up or down it doesn't matter) .
The key to this sound seems to come from the filter and contour settings. Contour with a relatively short rise time, instant fall time, sustain switched to "on", tone sources switch set to contoured.
Filter cutoff slider about 1/8 of the way up, peak emph about half way to 2/3 of the way up also, full keyboard tracking, contoured cutoff slider set to maximum. (prior to playing, set filter into self-oscillation and adjust cutoff slider to tune it to match the pitch of the tone sources on any given note as close as possible, then reduce the peak emph to original setting)
Of course, open both tone sources all the way in the mixer section.
Set the modulation rate to about 4 flashes per second, wave shape set to triangle, and manually use the tone sources slider with your left hand as a mod wheel to control vibrato.
I think you should pretty much get the same sound out of the MG-1 by now. Of course a little tweaking and experimentation with sliders might still be required to come even closer to the Liberation sound in that video.
Have fun.
EDIT Btw, although the Liberation and MG-1 share most of the circuit designs, there are some differences, aside from the obvious casing and modwheels.
The oscillators on the Lib have an additional waveform, triangle, and the pulse and square waveforms are reversed from osc 1 to osc 2. The envelopes are separate for filter and VCA, and have both a slider for sustain instead of a on/off switch, and a "release" switch, à la Minimoog D/Voyager.
