You mention your inspection angle as 72deg. If I'm looking at table 6.7 (testing angle) correctly, you need to follow procedure 1G (note 6)or 4 with F also noted. This would allow some options for UT. Unless the weld is ground flush then you should also use a 60deg. Note F also allows for further evaluation with 70, 60, 45, whichever is nearest to perpendicular. I would want to evaluate from face A ground flush, both sides of face A in the same plane, best to get it in the first leg.
Mr. Thomas,
I agree with your take on this. You are required to scan from both sides (per 6.26.6.2) and per Table 6.2 Note a you must use the thinner of the two materials to determine the acceptance criteria (moot point anyway as both 2" and 2.5" are in the same column of Table 6.2).
Regarding the evaluation of the indication, look also at 6.26.6.3. In my opinion, where it talks about "the maximum attainable indication" is referring to the max screen height. If I have to scan from both sides of the joint and one side shows the same discontinuity with higher amplitude, that is the side that has to be used for evaluation.
Mankenberg