The raw scores are not yet that useful on the WISC-V, in the absence of extended norms. As you note, if he does not have any 19s, the extended norms are irrelevant in any case. In any case, the -V has a better floor and ceiling than the -IV (more range on either end of the bell curve).
Please do not attempt to do subtest profiling yourself. This is a controversial practice even within the profession, and is best left to those with extensive clinical experience, if it is to be done at all. It may be that what you are describing as subtest comparisons is actually the interpretation of differences between index scores. That has more psychometric robustness, but is still a conversation you should have with the school psych, rather than going it alone, as the meaning of the index differences may not be the same for each child.
If exceeding time limits was a regular occurrence, then that is also worth discussing with the examiner. One of the subtests (block design) has an alternate scoring that does not do away with time limits, but reduces the impact of speed on scoring. This may be a source of additional normative information. If fine motor or mental processing speed is a factor, often this is evident in the form of relatively weaker performance on the PSI. In that case, the GAI may be a better representation of his actual overall ability. You may know that the GAI is preferred for GT kids by many.
