I am pretty much unsuccessful with Jtest4you deck, and the variant I made. Not sure how to study this one.
Recently, I tried Onomato Project, to study onomatopoeia vocab; and customize a little using {{type:Hiragana}}, Mnemonic, synonym Fields and WaniKani-like settings.
I feel that doing this one works. Maybe it is like @kikagakumoyo’s. However, it is for study vocab, not grammar.
Not really sure how you do JAP>ENG, but in my experience, for vocab, at least, the pairing that works best is (all EN meanings)->Kana, especially if there is no Kanji in the vocab. Actually, I tend not to care about Kanji. So, maybe, having Furigana is the best.
And then look up all meanings and examples in goo.ne.jp You are not going to remember only some of the meanings, are you?
But if you talk about Input Box, I used to be unsuccessful with that. How many sentences (by JLPT) can you read in 1 minute? Let's read Japanese sentences with self-checkable translations. [Anki/Spreadsheet/Desktop app]
Maybe, the best way to study grammar is to compose sentences, follow by cloze test and multiple choices.