@Bill ********
there is no "stay 6 month" visa option for you. If you get a 90 day Non-O visa before you come you will get 90 days when you stamp in and then you either get a year extension or nothing, OR you get a 60 day tourist visa, come in get 60 days and extend that for 30 more days giving you 90. That maxes out the time you can be here at 90 days too.
There is no "beg at immigrations", you either meet the requirements for an extension OR you go back to where you came from