I need to write up a proper info sheet for that, but in general you can wear together what you could wear together in real life.
For the body I used four layers so for instance you can wear a shirt (Under), aketon (Over), mail coat (Armor) and brigandine (Cover).
A gambeson is a lot thicker, and will take up the Over and Armor layer.
Full plate armor is the strongest single piece of armor, but too tightly fitted to be worn with mail, covering both the Armor and Cover layer.
Mail coat, longsleeve mail coat and mail shirt al behave the same layer wise, they just cover more or less bodyparts and costs more or less metal.
Brigandines, coats of plates and partial plate mail also only use the Cover layer, coats of plates are thicker but more expensive, partial plate is thicker yet but does not fully cover the body (needing to be worn with a mail coat).
The partial limb armor can also be worn over padded armor, the full plate version only with gloves and shoes.
Both kettle helmets and both sallets can be worn with a bevor (plate armor covering the neck and lower part of the face), great helms can be worn with a mail coif and mailed bascinet as well. Keep in mind that of these, only the great helmets fully cover the head, and those are not a thick as the other helmets.
Armets and hounskulls are both too large and tightly fitted to be worn with anything else, but offer good thickness and full coverage.
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Sooo the simplest set would probably be: Aketon + Plate armor (body), Armet (head), gloves + plate arm harness (arms), shoes + plate leg harness (legs). Keep in mind there are no more 'armor pants', since those are silly and caused some layering issues.
But there are trade-offs to each piece. Some cannot be worn with others, other are simply a lot cheaper to make (brigandines cost half of a plate cuirass).