Custom Item model size and position on hand

Hi everyone, I'm not an English speaker, sorry for my bad language, but I need your help.
I am new to the creation of mods and coding, but I managed to add custom models for my weapons.
Melee and range (with blender, great tool).
Achieve after many attempts that fit the size and correct position of the hand for melee weapons and partially for range.
But they are very large in the hot bar and in the inventory.
Thats the problem.
I tried modifying the Json file of the item with what I found in other posts, but nothing worked.

This is what i tried:

{
  "parent": "builtin/try6ham",
  "forge_marker": 1,
  "defaults": {
    "model": "xp_orb:try6ham.obj",
    "transform":{
      "firstperson_lefthand":{
        "rotation":[0,0,0],
        "scale":[1,1,1],
        "translation":[0,0,0]},
      "firstperson_righthand":{
        "rotation":[0,0,0],
        "scale":[1,1,1],
        "translation":[0,0,0]},
      "fixed":{
        "rotation":[0,0,0],
        "scale":[1,1,1],
        "translation":[0,0,0]},
      "ground":{
        "rotation":[0,0,0],
        "scale":[1,1,1],
        "translation":[0,0,0]},
      "gui":{
        "rotation":[0,0,0],
        "scale":[0.1,0.1,0.1],
        "translation":[0,0,0]},
      "head":{
        "rotation":[0,0,0],
        "scale":[1,1,1],
        "translation":[0,0,0]},
      "thirdperson_lefthand":{
        "rotation":[0,0,0],
        "scale":[1,1,1],
        "translation":[0,0,0]},
      "thirdperson_righthand":{
        "rotation":[0,0,0],
        "scale":[1,1,1],
        "translation":[0,0,0]}
      }
  },
  "variants": {
    "inventory": [
      {
        "transform": "forge:default-tool"
      }
    ]
  }
}

Do i have any error in the code or should it be modified in another way?

Thank you very much for your help.