Eeek! I see some come confusion here between 'lining' as in pinstriping, and 'liners' as in tank liners. Different animals!
Personally? -I just cringe when I hear of all these newbies pouring so-called 'liner' into their tanks almost routinely. Just 'cos they 'think' it's a good plan.
They need to know this: sooner or later that chemical you poured in WILL delaminate from the metal, And when it does, you'll be in more trouble than the early settlers (to coin a phrase). When it peels away from the inside you (or the next 'keeper') will have major problems stripping it out.
If loose rust is the problem with your tank, fit a fuel filter. If the tank is leaking, get a good welder to braze or weld it. Only as a last resort resort to the chemical tank liners.
Pinstriping:
I have a set of beautiful 'lining' brushes that came to me via my departed father-in-law who did signwriting for Carlton United Breweries in Melbourne, (ironically he was a tetotaller!)
I know it would take me a week of practice at least before I could get a pinstripe right, (even after a lifetime of painting/designing as a graphic artist). I could do that, but I've used pinstriping tape in the past, and it's SO easy. 2K Clearcoat over the top. Too easy.
The ol' bastard also left me lots of 'real' gold-leaf. Applying that is a real lost art, - it's real gold in sheets about 3" square that seem to be a micron in thickness! My Velocette might quite like it applied on the four and one quarter. Ol' Vic Bognor might turn in his grave... but his gold lining on the black enamelled tank he did is still very beautiful!