Predicate for item stack size

Not sure if this is a resource or datapack question, but I have a few custom items that I want to change the model being used depending on how many items are in a stack. For example, if I have 1 item in the stack it's a small pile of gold, 32 items and it's a new model that is a bigger stack, and if I have a full stack of 64 it's a giant pile of gold. Is there a predicate for comparing item stack size, or another method?
I am comfortable with making custom models, and getting them into the game, it's just the itemstack portion that seems to be eluding me.
Trying to keep it pure vanilla, so I want to avoid optifine, CIT ect.
Here is the current attempt (I'd also like to keep it independed of hotbar location as well, but that's the only thing with a count I've discovered, so far)
  "parent": "minecraft:item/generated",
  "textures": {
    "layer0": "minecraft:item/dried_kelp"
  },
  
    "overrides":
        [
            {
                "predicate":
                {
                "custom_model_data":2039
                },
                "model": "shallon/common/gold8"
            },
            {
                "condition": "minecraft:entity_properties",
                "entity": "this",
                    "predicate": {
                        "slots": {
                            "hotbar.0": {
                                "items": "custom_model_data": 2039,
                                "count": 16
                                }
                            }
                        },
                        "model": "shallon/common/gold6"
            }            
        ]
}