[Amps] Which Vg2 for 4CX1500B SSB ?

[Peter van Daalen]

Hi all, I am new to this list and need some help.

In various ( linear SSB ) 4CX 1500B PA designs I have seen various Vg2
voltages from + 225 V until +300V.

As far as I could recall, the lower the Vg2 the lower the IM3.

What could be the reason for designing a ( SSB linear ) 4CX1500B circuit
with  Vg2 at 300 V ?
End of all, one of the reasons to choose for a 4CX1500B is the relative low
IM3.
What are pro's and con's of such high Vg2 ?

EIMAC's " Care and feeding.. " does not resolve this question for me .
Who could ?

Thanks.
Peter, PE1ECM