Thanks for the patience!
I have now released a new version with a few changes, and hopefully a final fix for the loading custom js files problem. See change log and additional help text in the Custom JS tab in DFFS.
In addition to the hopefully last fix on the load custom js files, I have made a a hopefully significant improvement on the load time in large forms. Please report back how the load time changes with this new version.
Post your findings below, or use the forum.