Here's what I've got so far -

You get recipes to craft. Some are non-random from the Spiral Quartermaster, and others can be bought from the Stranger that sits at the Clockwork Junction at the halfway point of each tier. The Stranger's selection is random, so you need to visit him a few times if you want all the recipes.

When you craft a low-level item, you need to use Crowns, Energy and materials. There's a small chance (10%?) that you get a unique variant, an item that has a randomly selected bonus ability in addition to its normal abilities.

When you level up an item (with heat) it gains additional bonuses (are these always at levels 5 and 10? Are they random?).

There are recipes that require a low-level weapon or armor as a material. This is the part I don't understand, as getting this gear appears to require a significant investment of time and energy I have not accumulated yet.

I am of the understanding that if you use a weapon with a unique variant as an ingredient in a recipe, the item that comes out of that recipe will always have that unique variant. Is this correct? Can an item double-proc and get two unique variants over two tiers of crafting?

Does this apply for level-up bonuses as well? If so, then am I correct in thinking that the best course of action is to only use level 10 items when crafting higher tier items?

Are there any pratfalls to this, such as losing out on a better bonus higher up on the tier list if I stack too many bonuses early on?

Please enlighten me, Artisan Knights!