Obviously, I'm not a HSC marker like cem, but I have marked heaps of these responses over the last few years and hands down the biggest mistake I see with this section is that people dont answer the question (usually because they rattle off a memorised response). Prior to starting the essay, think about the question and whether it applies to your personality. Then come up with a list of reasons supporting that (around 2 - 4) and use that as the basis for the body of your response. You need to refer back to the question and your answer MUST show how your personality fits into the question/quote. Also, historians are NOT essential (take a look at the notes from the marking centre) - some people seem content to just analyse how historians view the personality. This is all very well and good, but if you arent answering the question, then you are limiting yourself in terms of marks.
With regards to Speer, I usually approached question B chronologically. I divided Speer's life into three stages (early life/Hitler's architect, Arms Minister and Nuremberg) and I analysed how Speer fit the quote at each stage. I found this to be a pretty effective quote to most questions, however, some may require a different approach so it's always good to maintain flexibility.
The personality section (specifically part B) has a reputation for being the most difficult part of the paper. I was pretty useless at it, but I did heaps of practice responses and eventually, it became my best section. So keep practicing and get your responses marked by your teacher.