Welcome!
I don't have my tables in front of me, so I wouldn't be able to give you a specific number right now anyway, but I will say that your GAI is unlikely to be substantially different from what your FSIQ would be, based on how the index scores are distributed. The GAI and FSIQ also are not likely to be the best representation of your optimal ability, given the wide differences between index scores. (I.e., yes, your lower PRI and PSI would depress your overall FSIQ/GAI scores.) That would be my reason for not giving you the GAI & FSIQ. They wouldn't add as much meaning as one would like, and might be misleading. I don't think you would be able to use the FSIQ for anything formal (e.g., Mensa) regardless, since the examiner isn't independently credentialed yet.
It would probably be more accurate to say that the minimum estimate of your ability is in the Superior range, where the two lower index scores are, since half of your indices are well into the Very Superior range. On face value, your scores would still be considered GT, certainly in language areas, and possibly in nonverbal reasoning as well. Depending on other aspects of your profile, they might also suggest a second exceptionality.
