If you have already been riding on the road then 80% of the battle is already won. The size and weight is like anything, once you are used to it you won't really notice it and in some cases it will actually make things easier, not harder. Personally I found the slalom and figure of 8 much easier on a bigger bike as they tend to be more stable. Your biggest enemy for mod 1 is yourself, the manoeuvres themselves are as easy or hard as you make them, I made them hard work and still passed so don't panic. Overall it's a pretty simple skills test and there is nothing there designed to catch you out. Just make sure you do your checks before you do anything. With mod 2 don't treat it as a test, treat it as a ride with someone and you will be fine. Again, there is nothing there to catch you out.