If you can get by with 'hunter changes', then start asking for lead changes over jumps. Mid jump, put your leg on him the same as you would ask for the opposite lead in a lead departure. Like:
1) Approach a jump in the left lead.
2) Make sure you can easily land and continue from the jump in the right lead.
3) Ask for the right lead mid way over the jump and continue on in it.
Using a log or jump pole for lead changes can lead to your horse dropping or dragging the lead with his hind feet by changing only in the front end. If your horse starts cross-firing doing these kinds of changes, you will have no choice and will have to teach collected changes. Bear in mind, that the more often a horse cross-fires under saddle (or even on a longe line), the more comfortable they get doing this and soon make a really bad habit out of doing it.
It is a LOT more difficult to teach a horse correct lead changes once they have learned to change only in front by either speeding up on forced changes or changes taught over a pole. These are both changes that rely on a change of direction and are really easy to get horses to change in front only.