Sim Hq guide relate to the first release version of AC. A lot has changed since that, AF is now much more optimised, same for smoke and reflections.
I have a single GTX 970 paired with a i7 4790k. I could run every setting maxed out if I want, but to avoid fps drops I use shadows on high, reflections on medium with high refresh rate and a custom PP filter (blackcelica mod, awesome natural visuals!).
For your hardware, I would suggest everything maxed out, except for smoke, reflection rendering frequency and PP filters. As these settings can cause some random stutters in a full grid. Also, Ultra settings for smoke and PP filters don't look realistic.
Use these values on your PP filters, but first download and install
Blackcelica PP Filter.
Filter: PP-Photo-CTP
Overall effect quality: LOW
It doesn't determine how good looking it will be, just the amount of effects added. We will add it manually via the custom PP filter and other settings.
Glare Quality: Medium
Anything higher looks like you have woke up one minute ago.
Depth of field quality: OFF
Let your eyes do the job of focusing. It will only introduce blurring.
Color Saturation: 97%
Just to make sure it doesn't look washed out
Motion Blur: OFF
Same as depth of field.
Crepuscular rays: ON
Nice sun shining effect
Heat shimmering rays: OFF
Looks more like drunk people sights on cartoons
Fast Approximate AA: OFF
Will only introduce blurriness as we are already using 4XMSAA
Smoke: LOW
Reflections: High
Reflection rendering frequency: HIGH
Max out the rest.
Hope you like these settings