Okay. In PRACTICE MODE, I finally beat 9+10+11...
...after 33 failed runs. At least 2-3 were done in practice mode after I edited the save data, which I will share how to.
Go into the folder with Minesweeper Plus on it, and go to your savegame.save.
I circled two numbers in green. The higher one is your listed time on Novice for Episode 3 Normal, and the lower one is your rank (0 = D, 1 = C, 2 = B, etc.)
Change the number on row 3 (the higher one) to something like 9999.00, and the number on row 5 (the lower one) to 0, then restart your game from the folder. You should be able to challenge 11 in practice mode!
Also, here's the settings in freeplay for the boss:
And the grid:
(download the image as a png and import it in freeplay)
Good luck, everyone. Until this game updates, at least.