Crosscurrents

The challenges in creating these larger puzzles are multiple. I could have created more than four single-grid puzzles in less time than it took to create this one, in part because each change required me to re-solve the puzzle from the start, to be sure I hadn’t broken anything unexpectedly. Still, the satisfaction of a working gattai that also follows the rules I’ve set for myself, it’s worth spending the extra time on one out of every dozen puzzles or so.

Rules:
Normal Gattai-4 rules apply. That is, there are four overlapping 9x9 Sudoku grids. Within each Sudoku grid, each row, column, and 3x3 box contains the digits 1-9. Overlapping boxes are shared between the overlapping grids.
The marked diagonals each contain the digits 1 to 9 exactly once.
Digits within cages do not repeat, and sum to the total in the top-left corner of the cage, if given.
Digits along arrows sum to the value in the attached circle.
Adjacent digits on solid green lines differ by at least five.

Estimated difficulty: 2.5 out of 5