Sorry I don't, yet, have experience with nut trees.

Do you have access to something like a local university or group which has plant and agriculture help? Here in the US most state universities have what are called agricultural extension offices who's whole mission is to help with farming and to a lesser extent gardening.

Have you asked someone at a good tree nursery / garden shop? If they don't know the answer they may be able to point you in the right direction.