I was waiting to see if anyone had anything to say on this. I am no expert but I can at least hop curbs and logs, I have no idea how people hop barriers but it sure is amazing. To hop a curb what I do is approach it with the pedals level at 3 o'clock. Just as I get to it I will pop a wheelie up and over the curb and instinctively at the right time pull up on the pedals lifting the rear wheel off the ground and the whole thing just follows through. I typically am on the bar tops or hoods some times but never the drops. For short hops I will just jump up and lift the whole bike off the ground level to the ground without the wave like motion of the front to rear hop.
I can see how the seat would get in the way of a big hop. It's not like BMX for sure. Perhaps for big hops they stand over the TT more so the saddle goes up behind your back? I don't know?