Here's a short video showing the rig in action
I saw that instructable yesterday.
The synchable-remote code was first implemented in SDM, mainly for stereo and multi-camera photography.
It has continued to be developed there.
You mentioned some problems in the Instructable, I suggest you try an SDM build to see if that solves the problems.
Just replace the DISKBOOT.BIN file.
You may also like to download Common_files.zip from SDM website, it has many useful features including powerful timelapse support.