Any character mod should have the start_inv list in some form, unless the character starts with nothing. What I actually meant by 'your character's Lua files' was not the character files from the game, but the similar files in a character mod.

Much less confusion, if you know how to do it, that is. You should never mess with the actual files of the game, unless you just want to mess around or test something, but it's exceedingly error-prone compared to the mod API approach. Yes, you can edit the game files after extracting them for testing things in the game, but I'd advise anyone to go the distance to set up a proper mod instead. I'm just trying to learn through others and share what I can. Note, this isn't actually a feature I'm looking to do. The readme in the data folder suggests extracting and then renaming the zip file for a temporary pseudo-modding solution. How to effectuate the changes with that knowledge is another issue. These scripts are found in data/databundles/scripts.zip in the Steam directory. I didn't understand what you meant by 'your character's Lua files', so I searched through all scripts for 'start_inv' with Notepad++'s Find In Files feature and found out you were talking about 'scripts/prefabs/.lua'.

Those two 'papyrus' will end up in the same stack. To give stacks of items, you just have to put in more entries of that item, like with the 'papyrus' here.

Here's an example for the Feather Pencil. You can find the item prefab names on the Don't Starve Wiki. There's a list called start_inv near the top.

Dont starve wiki item codes