i think of it this way: ive already made a wound by drilling the hole for the cable (or rod), if i make the counter sunk hole cleanly and only deep enough to seat the nut, then i dont think that adds a significant stress to the codit response. remember that the nut is crushing the tissue underneath in a normal installation. not as easy an entry for pathogens for sure but the cambium is killed none the less. also, on thicker barked trees, you may not have to drill as deep as the cambium to get a good seat for the nut. i might change my plan if the tree in question was a poor compartmentalizer, maybe go with a non invasive system.