It comes down, as all things surely do in whisk(e)y, to personal preference. It could be argued that CS of over 50% ABV are too powerful for the tongue and in fact numb the taste buds thereby distorting the full appreciation of flavour.
Personally I drink CS with a little water, as suggested above, added drop by drop until I like what I taste. I certainly don't use a formula to calculate the "correct" amount as there is no formula for life!
In a lot of ways I prefer CS whisky as I can vary the tatse to suit the/my mood. We all no doubt agree that the same dram can vary from the time it's poured until finished. And whilst we know it's the same whisky we drink each time, 'cause the label tells us so, depending on time of day, surrounding enviromment, what's cooking etc the variations in flavour from one day to the next can be startling.
CS has the advantage of being able to be diluted to suit, but the normal 40%ers ABV can't be increased and there are one or two that may benefit from that.