Electyrolysyisis gets it ALL out, and removes nothing but the rust. Not quick, but cheap and dirty and far superior to any of the other methods. The bigger the charger, the quicker the results.
Vinegar is fine for a neutralizer, and cheap ATF or motor oil sloshed on the interior will keep surface rust from hazing your shiny clean tank.
IMO coatings are bandaids. But if you've got pinholes, leaky seams or a really rare tank they'll get you by til you can off the bike or find a good tank. Never found any of them worth a dang in the long term. Electrolysis is still a good plan for completely neutralizing underlying rust before using them.