RIGHT NOW, I use a Sidewinder 10x42 with the 1/2 mil dot reticle. It is the ONLY case where I prefer the 10x reticle to the (larger) 20x reticle. This is because the 10x offers twice the hold points at 10x than the 20x reticle. IF you could use 20x magnification at HFT, I would opt for the 20x. But, as you know, Hunter Class allows for up to 12x scope power. So, this begs the question, "why not use the Sidewinder 4.5-14x, and have it set to 12x?" For me, it comes down to math. It is simpler at 10x power, and I don't feel like the "loss" of magnification costs me any shots. I do not rely on range estimation using the side focus (like the FT boys do). I find that at 10x magnification, I just can not get enough precision. So, I prefer to always use mil dots - especially since the target sizes (1/2", 1". 1.5" etc) are known.
I would actually prefer if we used metric distances. That would make the math easier (using the mil system).
In preparation for the coming HFT competitions, I am looking into 10x scopes with MOA reticles, as MOA "math" is much easier when target distances are set using Imperial measurements.