Thanks for the input. The document is read-only so people can always access and preview the latest version, but can't change the version everyone sees. Download the sheet to edit. Fields for user input are highlighted in grey throughout the Toolbox.

I've input reasonable defaults throughout the spreadsheet so users don't have to fill in every field one-by-one. They can change one or two fields and simply observe the effect. I think that's less tedious than demanding a series of inputs, though it requires a basic understanding of the layout and workflow.

The Toolbox is implemented in Google Sheets, and that's unlikely to change, so I have to work within the limits of a typical spreadsheet. It'll never be a program with pop-ups and customized input/output displays, as that's beyond the scope of the project. If someone else wanted to take on that sort of programming project, I'd be willing to work with them, but I sort of doubt that will happen.