I would probably say around a few weeks. At first it is very weird as I'm sure Mark will remember my first ride at Blackpool You also tend to overshoot everything haha.
Once you've got your head around it, it's just a case of applying what skill you already have but without brakes. Certain moves need tweaking for them to work without brakes. I think it also improves your commitment to pulling lines and reacting to what the bikes doing. With brakes you can generally stop for a second or two and think what you need to do, but without brakes you don't get that, and that's one of things I like most about brakeless riding.
Again, thanks for the comments everyone, they are very much appreciated!