If you are serious about developing skill and bravery in the room for your coaches, mentor coaching will add value. This works on the nuts and bolts of their conversations. While supervision works with self reported data from the coach, mentor coaching works with real data from live coaching (in a group) and from recordings of coaches working with those they coach (1-1). This can be uncomfortable and is, without doubt, the fastest and most effective way of developing extraordinary coaches.
If you work as a coach, we encourage you to go for accreditation with the International Coach Federation. They are the only professional coaching body who are interested primarily in the quality of your coaching conversations.