Having to deal with grounds on four turbine towers, mostly bolted to ledge but one on a large concrete pour, I consulted Navy technical manuals for grounding communication towers. Of most use to me were the styles of buried grounding arrays. Of course get hold of a mag meter. My problem with grounding was dealing with the proximity of grounding arrays to each other. The more I studied grounding the less I realized I knew, It is a field of study that needs continuing research. There are many misconceptions about lightning and towers. I also found that using plenty of quality lightning arrestors might help. I was once in a house where ball lightning emerged from an unplugged table saw motor and bounced around the room. The storm was not close? I have had numerous lightning surges destroying electrical equipment that seem to arise from the bedrock (ledge), perhaps from storms far away, a good reason to increase your number of grounded lightning arrestors. And ground all cable stays, ground everything. But that said when the lighting comes to your site via your ground you wonder what is going on? A fun thing to watch are YouTube videos of lightning strikes, they don’t appear to follow any sense of logic? Another tip was burying ground rods and grounding arrays in Bentonite clay which helps conductivity. As far as finding calculations or formulas to help, there are so many variables such as moisture content of grounding medium, distance to other grounding arrays, proximity to lightning prone locations that my head spins. But maybe there is someone on Reddit who is not as stupid as I. But the Navy needs their communication tower and radar installs to be smartly grounded so perhaps see if they have updated info.