I had almost the same doubts and restrictions some weeks ago, and I bought some of these flashlights to test them all. Up to now only 2 flashlights arrived, but it’s a starting point. Although my triple XP-L X6 is a light beast, I consider the MH20GT portability and weight nicer.
Maybe the MH20GT is more what you want (and me too). Read this post and compare the S3 (X5) with the MH20GT: USB rechargable, small 1x18650 thrower for camping/hiking with good CRI - #69 by alfas
Even if BLF A6 is not a thrower, maybe it can meets the portability x light output ratio in a very nice way, with its smaller head. I am waiting S2 and A6 to arrive to compare the light outputs of them all.
And I’ll also definetely consider this one when it comes out (I am following it already):
More info: ENEDED