Write a Python function `find_kth(arr1, arr2, k)` that takes two sorted arrays `arr1` and `arr2` and an integer `k`, and returns the kth smallest element from the combined sorted array of `arr1` and `arr2`.
The function should efficiently find the kth element without fully merging the arrays.
#### Example Usage
```python [main.nopy]
find_kth([2, 3, 6, 7, 9], [1, 4, 8, 10], 5) # Output: 6
find_kth([100, 112, 256, 349, 770], [72, 86, 113, 119, 265, 445, 892], 7) # Output: 256
find_kth([3, 4, 7, 8, 10], [2, 5, 9, 11], 6) # Output: 8
```
#### Constraints
- Both `arr1` and `arr2` are sorted in ascending order.
- `k` is a positive integer such that `1 <= k <= len(arr1) + len(arr2)`.
- The function should aim for an efficient solution, ideally with a time complexity better than O(m + n), where `m` and `n` are the lengths of `arr1` and `arr2` respectively.