Just playing around with god rays.
Like I had originally surmised, using the sharpness seems a better approach. You have whole integers to gauge your god rays on rather than decimal places that are overly sensitive.
Additionally, upping density for god rays impacts render time a lot more, since we care about such things even when negligible. At similar density to sharpness, or even just a bit denser, render time hits the 7 minutes or 9 minutes mark.
Also like I had mentioned, streaking is better with sharpness, as density actually makes the streaks denser and gradient out with other rays more, giving you smoother god rays.