Yes, all metal armor, both plate and scale, are in the 'ArmorScale' category.
(this could be changed, and in Classic, some mods have done that, but that requires changing the stats ... and adjusting recipes because recipes that worked before should still work of course.)
Although I haven't tested something like that I suppose that boosting items ignores the autoLevel, it is only ever regarded if items are actually created. If it was that easy it would take away the motivation for a lot of players to play games like DOS at all: the hunt for loot and new loot, over and over and over again.
If you created an item from another item, the original item is destroyed with all its applied boosts, so that would not work either.
You could use
use category Anvil on object ARM_Leather_Torso_Henchman_Madoc with transform code Transform2 parameters ARM_Leather_Torso_Henchman_Madoc,... autoLevel 1
to create a Madora's Armor from Madora's Armor at the crafter level, but that would not upgrade Madora's Armor but create a new instance of it, the original one with all possibly applied boosts would disappear, a fresh Madora's Armor would be created with the original stats, but a a potentially higher level than the original (depending on the maker's level).
You create a spear with
use category Dagger on object WPN_Branch_A with transform code Destroy1Transform2 parameters WPN_CraftedSpear_01,...
uses the transform code 'Destroy1Transform2' which can be found at the top of ItemCombos.txt and is
start transform code Destroy1Transform2
with using object do
object disappears
with used object do
set transforms param1
end transform code
means that the first object the recipe uses is destroyed and the second one is transformed into the output, the spear (so it is basically destroyed too). For this code, it does not matter in which slot you put the dagger and branch, the left or right one, if those two items are put into the slots, the 'crafting engine' simply looks until it has found a recipe which has both objects as input parameters, checks if the requirements to execute it are met and randomly executes one of the found recipes. With the spear, there is no randomness, because although there are different recipes with the same inputs, they can easily be differentiated by their requirement level, and the one with the highest level is executed. Requirement must still be met of course, the crafting engine will never choose the recipe that requires Crafting 4 if the recipe's executor has Crafting 3.
The recipe for spears with Crafting 5 introduces some randomness though, there are two recipes for a dagger and a branch with the same output, when used with Crafting 5, they both create the '05-spear' and additionally each puts a different buff on it, one a general damage buff, the other a critical damage buff (I think that's what it is, could be crit chance as well though). One of those recipes is randomly chosen when a dagger and a branch are combined by a Crafting 5 (or higher) crafter.
(This randomness is mostly used in the creation of spell scrolls, creating a scroll with an empty scroll and a magic inkpot & quill. Look up those recipes, there are many of them for each level of Crafting.)
Now if you really want to get deeper into crafting, I suggest you first read Rhidian's sticky thread
[Tutorial] Main Campaign Modding in the modding forum, it's an excellent start into understanding how the game works, the thread was made for DOS Classic but (almost) all info still applies to DOS EE. A lot of other threads in this sub forum are also very informative, especially the stickies. There is one which leads to a couple of Youtube videos where Larian has some tutorials for using the editor, dialog scripting, game scripting, world building etc.
And if you want to get deeper into crafting, you also should really get the editor, because if you install it, all templates in the editor folder should also automatically get installed, and simply looking at the Excels there (and maybe even the real stats, the .txt files) should explain a lot.
You can find the editor in the Steam Library, section 'Tools', there choose 'The Divinity Engine Enhanced Edition'.
It is pretty time consuming to start explaining all basics here in this thread that was originally only intended to make the dye recipes work.
(The fact, that English is not my native language does not help either. I also have a strong tendency to try to explain things into the smallest details, but if I explain something, I want it to be understood. My current project will come to a complete halt if I continue posting here ... ;-)
Most if not all the required information has already been posted in the modding forum.
I recommend the above mentioned thread of Rhidian, it's excellent and was also my start into modding some time ago.
Well, and as a tip: try to create 'believable recipes', an output of Leather Scraps for Dagger + Leather Armor is more believable than a boosted Armor ;-)
(For testing, it's okay though, because that should be as easy as possible.)
