Hmm, when I first spot or re-engage a second target, I'll call the compass direction. Following that I'll use right side etc. I find that's all I need, and while relative directions are nice to have, I find the accuracy of a clock system is unneeded if you have already attained that level of accuracy via a compass point. However, I do see the advantage it brings if you are engaging multiple opponents at different times- for instance, an unmarked opponent could approach from the rear, while you are facing another to the front. Rather than call out SSE, for example, you could cut out the mental process and say 'Pyra on our 6'. Bearing in mind for this example, 6 is a terrible number to use, and the use of a secondary clock radial would only find usage in unorthodox calls, such as 5, 2, etc . However, this degree of accuracy isn't needed if the target is already engaged, as you don't require that extra level of accuracy, as the general position of the target is known. It's only when the target is rapidly introduced to a preoccupied and potentially unaware crew that this system would be beneficial.