A minor clarification from Stuart's post.
I just called Pearson to clarify something. Yes you do get a new set of scratchpad only when you request it. In other words if I have started AWA and want to reuse it if I want to in Quant.
During the tutorial PR (and others I believe) recommends dividing up the scratch pad into 4 boxes with each box containing ABCDE. The clock for me is a major distraction. I tried the following recently that helped me. In each box number the questions (1, 2, 3, 4, 5.... 37). At every 5th question put in time remaining. For example at 5th question (2 min/Q rule) should be 65 min remaining. This kept my eye off the clock and helped keep an eye on pace. This strategy was particularly useful for Quant.
Secondly for those who have used mechanical pencils all their life (engineers) the marker and scratchpad may shock you. I bought it and found it difficult getting used to writing with it. Luckily after several practice tests using the scratchpad has been great.