I ran out of time yesterday, but I was going to ask you which of the AWS codes you were working to as they are numerous.
Gerald has given you about the best reply considering that the particular code was not mentioned directly. Butt joints should be at least nominal base material thickness due to the EOR's design calcs. Table 6.1 and Fig. 5.4 address the +/- visual acceptance criteria in D1.1.
Hope this helps.