You are right that Oahu is a better bet, and even Maui has a few choices, vs the almost non existant hobby on the Big Island. Depending on your budget, maybe you could do a day trip to Oahu, or fly an Oahu provider to you.
There are some small possibilities on the Big Island, but it's usually hit and miss and a matter of timing. Occasionally Oahu ladies tour there, and sometimes Mainland providers will tour there. It's a matter of timing if you get lucky and there is someone there the same time as you. There was a top lady in Kona for almost all of April and May, but she is long gone, so you missed her by a few months. Since you mentioned you are on P411, you may have noticed a lady advertising that she will be on Big Island in mid October. Don't know if you will be there that long. Back about 7 to 10 years ago there were actually two agencies operating on the Big Island, that had some decent ladies available, but they are long gone now. Over the years there have also been a few highly rated indies that set up shop there for a few months at a time. There are a few tantra types in Puna side, but even their ads come and go, so don't know if they are always available.
All you can do, if you are not willing to head to Oahu, is check the ads every day, and hope you get lucky. Check all the sources you can. TER other cities ad board, eros, backpage, p411, etc. As of today, I can 't recommend anyone. Tomorrow that could change