This can be very annoying and time consuming modification. To me the presets in L100 are pretty much useless, that's why I decided to change them. In theory you can rewire them to random/favourite setting but the amount of connections, wires and unnecessary work would be too big.
When you look at the preset tabs you will see two for lower manual (they have seven pins each, one for each drawbar) and four for upper manual (nine pins each) which looks like this:
I pictured each pin linked to its corresponding drawbar for each manual:
To change the presets you will have to turn the tabs upside down and resolder the wires. The other ends of those wires are already soldered to the intensity terminals on the drawbar bus. Their values are 0, 2, 4, 6 and 8 so if you want 856300001 make it 846400002 or 866200002 instead.
It's best to draw the layout on the piece of paper. Sometimes changing harmonic value from 6 to 4 can greatly simplify the whole work. You need to plan before you do it. Take your time.
The is an example of 866444224:
I preset my L122 to: