If you are able to recall anything about the test afterwards, you have probably failed! You need to know that there will be digits missing and that you have about 1.25 secs to scan the screen. You will have NO capacity to recall what you saw!
On the same subject, the best tip I read was to move your chair as far back as possible from the monitor. This simple trick means your eyes have to scan through a smaller angle and I found it remarkably helpful.
Also, don't panic if you have a blank on the day. You almost certainly won't get all four dials correct. I averaged three and on at least one run, I only got two.
Most of the tests at DLR can be seen as a test of your ability to cope under pressure and keep going without giving up. If you feel you have loused a round up, try to put it immediately behind you and carry on. You will, hopefully, be pleasantly surprised. As you will hear on the day, many of the tests are doubled such that they take your average over two tests.
KT