Scroll speed and vertical/horizontal lines

[DandyJeffrey]

So I use vertical/webtoon mode a lot and I'd like to adjust the scroll speed so this would be nice to have in the settings tab. Should also be able to toggle smooth scroll on and off.

Also how do you get rid of those small thin lines that happen between the page breaks? They don't disappear even when you set the margins to 0px. Here's what I mean: