I've restored the tank on a 3.0L Montero, so I don't know if this will help you much or not.

However, if there's any way to save (or replace) those tubes, do it. I had one tube outlet I let get clogged with the POR15 and the "check engine" light was on forevermore afterward.

87 Montero, bought new, by me -
88/89 intercooled Starion Turbo engine-
with awesome audio.