Castrol brags about "clinging" but Castrol brags about other things that most of us on here have found to be more "marketing" than actual facts.
Synthetic oils have been proven to flow better under most conditions and to have better resistance to most destructive conditions than petroleum oils, but as far as "cling-ability", by definition, that "flow-ability" is a direct contradiction.....
Synthetic oils will not be as "sticky" as oils that have more of the "viscosity improver" (polymers) added to them. If you want "sticky" oil, add some of the STP type additives, there is a NOTICEABLE difference when the VII is added, even in small amounts.
It's easy to check out, just pour some comparison oils in a glass jar, tilt them and watch the oil coat the glass and see how long it takes to drain back to original level...not very scientific, but it shows the difference nevertheless.
It's a good activity for those Saturday afternoons that the weather is perfect for staying outside, the smoker is going and the day is just one of those football days....
see ya
Rando