May I know what car you are driving?

If use Petron Blaze Ron 95 it will reduce knocking tremendously.

On the other hand if your car is using old Japanese engine (80s to 90s JDM type) than you may wish to give a try to Caltex Techron Ron 95.

If either Petron Blaze Ron 95 and Caltex Techron Ron 95 cannot solve your knocking problem then you may need to use Ron 97 petrol.

I believe (maybe I am wrong) it has nothing to do with thinner or thicker engine oil.

I owned 2 modded cars one is Satria with Mivec engine and the other Accord with H22A engine which both are high compression engine and it was suppose to  to use higher Ron petrol eg Ron 97.

My Satria is currently filled with  Caltex Techron Ron 95 and the engine oil is Hi-Rev 15W-50 (Semi Synthetic) so far so good no knocking but it need to change engine oil at 4,000 km interval.

As for the Honda is currently filled with Petron Blaze Ron 95 and the engine oil is Qmax 5W-50 (Fully Synthetic) so far there is no knocking and the engine oil will never dry-up or evaporate therefore I only change the  oil at 8,000 km interval.

Pls see file attachment of the pics of the engine oils that I am using for my Satria and Honda.