What should be PDCP sequence length for CA in case of 5G NSA ideally set?

Hello Experts.

What should be PDCP sequence length for CA in case of 5G NSA ideally set?

The length of PDCP SN is either 12 bits or 18 bits.
It is configured by upper layers.
18 is for high throughputs and CA.

But high value leads to low data volume with pdcp overheads.
It gives high throughput and less packet loss but drawbacks too are high.