I too use Vallejo Model Colour 70818 Red Leather for BR bauxite (it's 136 on the display rack).
Some may argue that it's a little too 'orange' out of the bottle, but over a black primer it darkens down some what, and weathering grime also darkens it some more.
Vallejo paints are readily available online.
I'm not trying to shut the world down, as you say, I'm merely using the government's own words.
I'm sorry that you seem to feel that this is some form of personal attack on yourself, and the publishing industry, that was certainly not my intention.
Content or distribution won't be the problem, printing will be.
I very much doubt printing hobby magazines will be classed as essential work, and certainly can't be done from home.
Depends how much you thin it, how many coats you apply, how big the locos and coaches, etc, etc.
There are too many unknown variables to such a question.
It will also go further if you airbrush it, rather than hand brush it.
Interestingly, during my usual Sunday afternoon session at the workbench, presenter David Mellor declared an interest in railways, and played a number of railway inspired/themed classical pieces.
Railtec do a couple of internal user wagon sheets in 4mm, they may produce them in 7mm too if requested.
https://www.railtec-models.com/showitem.php?id=1799