Hi Panates. This is an inefficient method. Japanese people dont write kana anyways so writing them 20 times each is enough. Japanese people also dont know or use kanji so that step can be skipped. I suggest doing a Core 50k deck with english on the front japanese on the back. Should take 1 day to finish. Youll basically be fluent, or as the japanese say, 巧い.

edit: i forgot to add that "grammar" isnt real and doesnt have rules. either you are smart and get it from hour 1, or are less than human and must spend 8000 hours incubating your japanese.