Re aging in nylon...
I have a big box full of left-over spools of nylon, dog-ends, etc, collected over about the last 40 years. Lots of different brands and diameters and standard and low-diameters types. I got them out one day and tested their breaking strains. They were all perfectly good, apart from one spool of Orvis Superstrong, which was knacked for some reason. Put me off ever using Orvis Superstrong again. My conclusion was that, stored in a cool place in the dark, nylon is fine for many, many years - but you can always get a bad spool.
My preferred low-diameter is D.A.M Tectan Premium Plus, which gradually became more and more like hens' teeth to find, so I stocked up on it a good few years ago. It is now discontinued, but I have enough 300 m spools of my favoured breaking strains to last a good few years... especially at the current rate of use!
I don't buy Marmite, but I don't mind it. ?
I don't use Stroft, but I've nothing against it.
Col