Yeah, if the crafting option is gone, the plugin probably found an error on load and didn't load the rest of the way. Trust me, I've seen enough of that problem while I was making it.
I don't think I should share my email address on a public spot like this, but you can direct message me on discord Ramza#3215 and send me your edit that way.
The n-3 and 4 thing is confusing, I'll admit. It's only used to find partial matches, so for just getting it to work with a 6 item recipe, we don't need it right away for testing purposes. If you look at the difference between my n-1 and n-2 sections, which are commented, you can see what you need to change to get it to check for n-3.
The most important change is going to be to edit the recipe list struct to accept more than 4 ingredients. This is going to involve adding in new parameters, giving them a new name, and parsing them the same way that the first four ingredients are parsed in a recipe. The actual parsing is handled right after the help file section ends, so you can have a look there and see what I do to convert the plugin parameter into an actual object.