You would have to go through and alter the grammar concept descriptions for the cloze cards so they don't contain the answer, as per the のに example.
What would be really useful is if you could set up the deck so the example sentence on the front randomly changed between the available example sentences for the concept, without having to make new cards or disrupt the scheduling for the .grammar point/fact. For example, のに would appear as >毎日漢字を勉強している○○よく覚えられない・覚えられません。
on one review and the next time you review the card/fact it will randomly be one of the other example sentences, say > あの人はピアノが上手な○○めったに弾きません。
My deck has that concept description already "clozed", in a way. Here is how it appears:>Contrary to everybody’s expectation based on the sentence preceding [x], the proposition in the sentence following [x] is the case.>Even though; despite the fact that~; although; but; in spite of the fact that~
Pretty sure I didn't manually change this, either. In fact, they all seem to be like this. Maybe the decks we are using are different versions. As an aside, it's kind of amazing just how much as been generated just from one person who decided to work on bringing those grammar dictionaries out of their dead tree prison, a few years ago. The English language Japanese language learning scene online has it pretty good.