Do you have any protocol recommendations to get longer insert sizes?

To generate longer libraries, use the QuantSeq-Flex First Strand Synthesis Module (Cat. No. 166). The protocol is outlined in the QuantSeq-Flex First Strand Synthesis Module User Guide (166UG323).

The figure below shows an example of longer libraries achieved using this protocol.

Figure 1 | Bioanalyzer traces of QuantSeq FWD (Cat. No. 113) and oligo(dT)-primed QuantSeq-Flex libraries prepared from 500 ng UHRR input RNA. RNA was denatured for 3 minutes at 85 °C, with either 1 μl Oligo(dT) Primer from the QuantSeq-Flex First Strand Synthesis Module V2 (Cat. No. 166; blue trace, RNA+dT), or with 5 μl of the standard QuantSeq FWD FS1 buffer (red trace, std.). Average library size is increased when RNA+dT conditions are used. Libraries were amplified with dual indexing and 13 PCR cycles.