If you have decided to use dropping the rope principal, then I would suggest you try to think of how you would respond if he was a distant relative or a co-worker. In other words, your emotions would not be the same.
Something I notice a lot in posts by LBS is how they feel they have to check on the child when the other S has them. No offense, but if I suspect that that is an "excuse" for contact, don't you think he might wonder the same? Another thought is that he might not answer your call b/c it is saying you don't trust him to care for your S.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!