I have an M21D (55mm head). It has an XHP 70.2 5K emitter with light orange peel. It is a beast for output. But, no one would call it a thrower.
At your 15 meters the hotspot might be 2 to 3 meters wide with more than double that in very bright spill. It will light things up just fine on max at 100 meters just due to sheer output. I often use it in my backyard to keep track of the dog. (BTW these numbers are just rough guestimates, but not far off, I think)
On the lowest level it will fill my main hall 15x2 meters with plenty of light. It is quite useful for my purposes. However, I don’t find myself in a position to need to see things further than 100 meters. If I do, I have dedicated throwers.
I don’t have any lights using the SST70. There is a thread on it HERE.