Thanks for commenting and questionning!
European format is usually DIN A4 (8,2 x11,8 in). Around 54 pages and indeed mostly hard cover. That makes them quite expensive so it's a tough passion to cope with when you're young. Soft covers are sometimes still used from new projects with not too many copies involved. If you go over 3000 copies in one batch, you might consider using hardcovers.
In my case, self-publishing was with my personal saving but mostly with various successful crowdfundings. In total I printed and sold till today around 1500 books (of that Devlok's story), including French and English versions over book 1 and 2. A big part is already presold through the crowdfundings and the rest I sell online, in a few physical shops but mainly in fairs and other art related events.
Mangas are great, the Japanese really quickly came with their own narrative and graphic style. My favorites are Akira, Ghost in the Shell and BLAME!
RE: How I paint comics: The Techno-Templar #43 (+Details)