6GR qualfied thickness range

I just combined a WPS 6GR with SMAW and FCAW
It has different thickness T1 = 12.7 mm and T2 = 25 mm.
So, the thing is i need to clarify the qualified range for the thickness.

Groove weld qualification follows thinner thickness.
Why dont you make a PQR with standard pipe.
Read more how to prepare a PQR D1.1 2015 prepare pWPS notes