First of let me thank you for taking this up and bringing it back to life. You've done a fine job!

Now for the suggestions. Unit Tests are a great idea, and I understand the pull-down menus help weed out typo mistakes. But currently it takes too long to enter stuff, especially if we want to create multiple tests that are very similar to each other, covering different starting variables for example.

Having cut-and-paste of the various nodes would help a lot!