Most of the markers I reviewed have water based ink, some are alcohol based. Even if the latter, they are very neutral in smell.
I mostly use sizes 0.5 – 0.8 for drawing, but for filling in the larger areas I naturally try to use the larger ones, 0.9 – 1.2. I also noticed that size 0.4 in certain brands is similar to 0.5, but 0.3 in all brands is definitely too thin for my taste. Except for fine details. More about this in the actual reviews.
Many of the markers I have ordered online, usually from Pen Store and Unfade. But I also buy them in person from my local shops Make Your Mark and Unckan. If something else, it’s stated on the review. Molotow Blackliners I always buy directly from the Molotow Helsinki store, not online.