Some good questions.
D1.1 2015For your GMAW short circuit procedure qualification on 1/8" plate... If you are not back-gouging on the PQR be aware of Table 4.2 Note "C"
I don't see a lot to stand on when it comes to making a performance qualification test that is less than shown in the Clause 4 figures and tables.
However, Here is something to chew on from an "official interpretation"
https://www.aws.org/standards/page/interpretations-d11The interpretation question is specifically about root openings, but the response from the committee says a little more if you are willing to read it that way.
Inquiry: Is it permissible to have a 0-1/16-in. root opening between the test plates shown in Figure
5.22A?
Response: Yes. The Committee has not specified any tolerances for the dimensions in Figure 5.22A. The
dimensions shown are nominal and need not be exact. (The contractor may place dimensional
tolerances on shop drawings, such as those required in 3.3.)The dimensions for the test assembly are *nominal* so if you want to fight about what "nominal" means and apply that to base metal thickness for your test assembly with the sustaining argument that the "contractor" can place dimensional tolerances' on drawings..... maybe you have a leg to stand on. But that still leaves the question of qualitied thickness eh?
But I think a 3/8" short circuit test assembly is not that imposing for a task.... My first semester welding students were able to pass an open root limited thickness GMAW short circuit in all positions.
Anyhow... Food for thought.