Relax, I was working on it. A good question, because I'm forced to explain how to do it practically.
I didn't know the LTC1799, so I checked, and this one could run the SK1 as well in the same way.
I'm not sure if the processor of the SK1 use a crystal, it (L10-495) looks like a coil to me :
http://www.xs4all.nl/~samzen/synth/sk1_clkin.pngAnyway, as you can see in the top left corner, it's not necessary to remove it.
You only have to remove C15, and cut some lines.
To illustrate this, I made a closeup of the pcb situation :
http://www.xs4all.nl/~samzen/synth/sk1_pcb_clkin.jpgIn the
green rectangle is C15, to be removed, which gives the
red spot available as a soldering point
for the clock output from e.g. your 1799.
The
blue things are the cuts to be made of the copper lines.
And the
yellow spots are the nearest point to derive the power for the IC, zero and 5 volts.