Ok to change the look of items on floor,bag,and char screen. You open StateItem.wil with hh8 and find the item your looking for. You then get the number of the image and put it in FLD_ImgIndex.
Now for the actual armour to show on your character. Open Human.wil and find the armour you are looking for, you need to count down how many armours it is, until the 1 you are using. So number 1 = BaseRobe(M)
Number 2 = LightArmour(M) so if the armour you wanted to use was 30 armours down the list, you would put 30 in FLD_Shap.
If you are using graphic folder (Human), then each wil contains only 1 armour witch makes it a bit easier to use. Simply get the number from the .wil and put it in FLD_Shape.
Hope this helps.