Effort does cumulate, so there is no need for everything to be sent in one cycle. However, to your suggestion of sending 40 calls in one cycle and 40 letters the next... there is really no point. 40 calls will almost definitely not get him to consider you and you essentially gain no valuable information by sending them, so why only stick your toe in the pool when you can jump in with minimal increased effort? It pays to do it in the same cycle.