nothing wrong will happen by using high octane in your brand new cg at least few full tanks..
High octane is good for engines having higher compression ratios. Cg isn't high cr.
It is always recommended to open throttle in slow and smooth motion. At low speed only pilot circuit of carburettor is active therefore it gets hard for bike to respond appropriately to sudden sharp throttle responses. At higher rpm three circuits are involved and they can compensate for sudden change in one mainly main jet circuit.
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