That bracket and mounting method looks solid. Nicely done there. And thanks for the pics!
Now the harsher part...
... Even with my 23" I can see miles down the road from the spot beam and quite far to the sides with the flood pattern...
Miles? I highly doubt it.
I am a flashaholic... I am addicted to designing, building, and modifying flashlights of all sorts... I am constantly on BudgetLightForum and CPF, others...
Miles of throw is not going to happen unless you have a 75-100+ watt HID searchlight, one that has a 7" diameter reflector 5" deep. And even at that, the beam will only be 1 degree wide at 1.5 miles or so... a pencil beam as we say. (That's not to say 1.0mile throw cannot be achieved by any other light, it can... but you'll have more than $200 into it, and it sure as heck wont be a multi-emitter light with a 1.5" deep reflector like this light bar). And this 75w HID searchlight would be something like a MaxaBeam... a $1900 light.
There is no way you are getting more than 100m of throw based on the dimensions at Auxbeam. They say 80 emitters at 3w each, 24,000 lumens of output, 240w total. That's probably a stretch. That would be running each LED at max, which is not likely with whatever driver board they are using. They're quoting hypothetical max potential there.. 300 lumens per LED.
That being said, that doesn't mean it's a **** light bar. But you will most certainly get more distance and throw out of a pair of round 6.5" offroad lights.
Glad you like the light bar, I am sure that for what you want it for, it'll do just fine.