that app is a guideline . i used it (combined i5-8600k with GTX 1080) with a bottleneck less than 5%.
i5-9600k is a good cpu (for a 350€ pricetag) , with very good overclockability, and will work ok with 1060.
Might wanna consider Ryzen counterparts for better compatibily/bottleneck with your 1060. (if you're planning on playing strategy games i STRONGLY reccomend hyperthreaded cpus)
PS. Atm i'm using i5-8600 (4,8GHZ OC) with a RTX 2070. in a few games like SCUM or Metro:Exodus i noticed my CPU had several moments when it was idling (worked at 35degrees while GPU was at 65degrees).