I was just comparing the first condtional and second conditional in English to the same grammatical structures in Portuguese. There's no way mixing up real and unreal/imaginary would work in Portuguese. I didn't ask, but something just tells me, "Don't even think about trying to the same thing in Portuguese." So, I'd say be very cautious with it in English. It doesn't happen often. There would have to be a good enough reason for it. It would have to be justified somehow. And remember, hypothetical language is difficult for some students to grasp in the first place. They can readily understand the grammar form, but when it comes to using it spontaneously while speaking, it's oftentimes not easy.