I was thinking of doing that for Biology - apparently we're doing the Human Story, but a brief look at the Genetics option made me feel that it was going to be more enjoyable.
But the problem is that (I think) the other Biology classes will complete the same option, and therefore our trial paper would only have questions based on the option that we have done.
But if you can balance two options and learn one effectively for your trial, and the other option for the HSC, go for it