I think once you settle into it, it goes quite quickly and before you know it you're finished. You aren't required to wear headphones for it, but I did to enable me to get used to them for the other assessments and also to block out any distractions. Take your time with the practice (I did the practice twice).
With the image one I think they're looking for things you definitely saw, don't randomly guess, but concentrate and scan the image.
With the two hands, they're looking for accuracy and speed... You're allowed outside of the lines, they're looking to see how quickly you correct it and get back in the course. I went faster on the straight and slower on the corner sections. I set the volume loud enough to hear it, but not too loud for it to be a distraction. Hold the joysticks lower down (less sensitive) and again make the most of the practice.
I've not completed my MMI yet, just a waiting game but it depends on which depot you've applied for also.
I'm in the catchment for several depot's, but Faversham is my preference.