Thanks everyone for there positive feedback, its nice to hear and also be able to help.
Chaoticone, I agree about the button to, people just generally want to automate the process and not have a full understanding so therefore it makes it harder to diagnose future issues,
With regards to the acceleration and velocitiy, do you have a guideline that you follow? For example should acceleration be 50% of of the velocity? etc etc or a certain % of the velocity as a guideline. I have generally just played it by ear and gone for something thats not taking off like lightning then jerking to a halt.
Thanks
Chris