Somehow, the welding engineer will confuse with which samples will be used in PQR preparation for applying the WPS correctly in accordance with Project specifications. Special on Tubular and Non-Tubular application. There are short guideline may help you to choose the samples wisely as below articles and file:

What is CJP in welding in Tubular and Non-Tubular

AWS D1.1: WPS variables – Joint design

Back gouging in welding

WPS/PQR – JOINT DESIGN

AWS D1.1 tubular vs non-tubular and PQR preparing guidelines