Thanks Booxtor, that's really a huge collection!
I added templates for the scribble app in 1200x1200 to my original post, see
https://www.mobileread.com/forums/sho...&postcount=282. You can work with them in both horizontal and vertical mode now - without getting those borders you usually don't want and of course without changing zoom settings (which leeds to squares being more than 5 mm x 5 mm)...