BP4417, I endorse everything you have said about water treatment and boiler storage.
I have had to fight the unbelievers in one steam preservation group. I mixed my treatment chemicals so that dosing was easy. One litre of my mixture to every 1000 gallons of water. I reckoned it couldn't have been easier. But no; a couple of know alls told everyone that another mob didn't use anywhere near that much. This, of course, was not true; they just did it differently They added two different chemicals neat; mine were both dissolved into one solution. The end result was that the work of a Chemical Engineer with an Open Boiler Ticket was ignored, and the the loud mouths won (because I couldn't be there all the time to check the dosing ).
Some time later, the loco blew a flue tube and failed. Inspection showed an obvious lack of correct treatment, and the Boiler Inspector hit the roof.
It's an expensive and time/labour consuming way to learn.