If you plan on riding gravel at all, I would go with the gravelking SK vs. the GK slick. I used the slicks in 28 mm as a pure road tire and found them to be quite fragile. The sk however is great, very flat resistant and reasonably fast on pavement (I ran 32s on a different bike with more clearance though).
I was able to fit the 28 gk slicks with a DT 460 rim Into Shimano 5800 calipers without maxing out the clearance.
My absolute favorite is the good old Panaracer Pasela. They are cheap, light and have very supple sidewalls while the tread area is well protected against cuts. And they look classy too imo.