It is a fair question whether just practicing my sudoku books is the right way to make the US team these years, since I have written for the qualifier several straight years and tend to write certain styles a lot. But I'm glad to see some of my sudoku forms are on this year's WSC including one of the ones highlighted here, so practice on these Mutant Sudoku may actually work well for the world championships too.
Place a single digit from 1 to 8 into the empty cells in the grid so that no digit repeats in any of the six outlined regions or the 12 "rows" that pass through opposite sides of each quadrilateral.
Tight Fit Sudoku
Place a single digit from 1 to 9 into the empty cells in the grid so that no digits repeats in any of the rows, columns, or outlined regions. There are some cells in the grid with slashed; in these cells, two digits must be entered with the smaller one entered above the larger one.
Place a single digit from 1 to 9 into the empty cells in the grid so that no digits repeats in any of the rows, columns, or outlined regions. There are some thermometer shapes in the grid. The digits in these thermometers must be strictly increasing from the round bulb to the flat end.
Reader hagriddler shared his own Excel notation for how to look at Isodoku in a flat form. The diagrams look a lot like how my co-author Wei-Hwa Huang encodes these puzzles in his software for construction/checking so with his permission I'm sharing his picture. Isodoku(2)