There is a useful and cheap SGROW unit that has both 660 and 830 (or thereabouts)--a friend bought one, and is pleased with it, and I have on order the Red Light Man's small all 830 unit, which costs $135 Cdn, and looks good for powerful local use. Ari Whitten's "Ultimate Guide" book has much useful info on dosing, and seems pretty good--multiple refs show he has read much of the research, though takes a strongly pro approach. On the advice of this book I bought a Platinum BIO 300 for overall use, and am pleased with it--not too expensive. But one has to be careful using these powerful lights--if I bow my head to get the full force on my scalp, I can feel a bit stunned. One can use either the red light or the NIR or both--separate switches. But I still have ME!
I have also just bought the Konftec Emlas ear thing, to try to treat both HF hearing loss and some tinnitus--too early to tell, but maybe....