I would absolutely recommend against choosing two - unless you have a stupid amount of time, you will not be able to revise either of the texts to a sufficient level of depth, and in text response in particular, this can be highly detrimental. You want to be at the point where you basically know your text inside-out by the exam period; for VCE students, this is not going to happen unless you write/plan for many, MANY prompts before the exam begins.
Re: the texts themselves, I don't know Henry IV very well (although I have heard it's a great play, albeit potentially a bit confusing if you don't know the history very well already), but I would just like to take a moment to champion Ransom as a fantastic VCE text. If you have read The Iliad (and I STRONGLY recommend you do if you haven't, even if it's just books 1, 16, 22, and 24), you will realise there is a wealth of interest within the text, and Malouf does a fantastic job with both intertextual devices and his general style in envisioning ideas concerning personal identity, storytelling, and psychoanalysis. It's an extremely rich text, but also a very accessible one if you bother to do the research, and really I think it's much more appropriate for VCE students than, say, Interpreter of Maladies or some of the other stuff that exists on the text list.