good move on snagging that Korg MS10...
Eye repaired trashed MS10 for some Bloody girl in Chicago noise scene.
sort of want one... yet always fighting SpaceWar with gear
have my 78 korg35 ms20 & x911 expander...
plus bunch of other Hertz cv gear...
if you want some expander VCOs have an old easy design for LM324 look at this...
made some of them & modular LFOs with that chip
stripboards... confirmed that Hertz VCO design is functional w/Korg MS series