Placed Feature Count control

So I started optimizing my pack so each placed feature is only called on once in every biome. But I ran into the problem that when trying to set how frequently the feature spawns, count 3 is too little and count 4 is too much. What could I do to fine tune the spawning of a feature?
Here is my current json:
    "feature": "limbo:smaller_tree",
    "placement": [
      {
        "type": "minecraft:count",
        "count": 3
      },
      {
        "type": "minecraft:random_offset",
        "xz_spread": {
          "type": "minecraft:weighted_list",
          "distribution": [
            {
              "weight": 1,
              "data": {
                "type": "minecraft:uniform",
                "min_inclusive": -5,
                "max_inclusive": 0
              }
            },
            {
              "weight": 1,
              "data": {
                "type": "minecraft:uniform",
                "min_inclusive": 0,
                "max_inclusive": 5
              }
            },
            {
              "weight": 1,
              "data": 0
            }
          ]
        },
        "y_spread": 0
      },
      {
        "type": "minecraft:heightmap",
        "heightmap": "MOTION_BLOCKING_NO_LEAVES"
      },
      {
        "type": "minecraft:biome"
      },
      {
        "type": "minecraft:block_predicate_filter",
        "predicate": {
          "type": "minecraft:all_of",
          "predicates": [
            {
              "type": "minecraft:matching_blocks",
              "blocks": "minecraft:air"
            },
            {
              "type": "minecraft:matching_blocks",
              "offset": [
                0,
                -1,
                0
              ],
              "blocks": "minecraft:black_concrete_powder"
            }
          ]
        }
      }
    ]
  }```