As a developer it is currently too difficult to properly preview the way a UGC accessory will look when uploaded because of the automatic scaling.
Here is an accessory in my studio place (applied using Humanoid:AddAccessory()):
Once I uploaded the item and previewed it on the site it looked like this on my avatar:
Even after reuploading the item twice I still haven’t been able to correct this issue, and constantly reuploading accessories is expensive. Please add a way to properly preview the way an accessory will look before paying for an item upload.