Not only Ruder but also reading Hochuli is very recommendable.
I think I am a scroll person.
During my first week of ipadding I found myself mostly holding it in both hands, left and right thumbs on the black margin. Easiest appropriate navigation is scrolling with one thumb during reading (focus of attention roughly in the middle of the screen), occasionally tabbing top left to go back somewhere.
What I like best so far are all kinds of navigation that don’t require my hands to leave the device. This might be different when the ipad is laying on my lap. But also then I mostly have my hands resting next to it.
Tabbing somewhere down right to get to the next page in a paginated layout is comfortable as well. But a bigger gesture like swiping with two fingers would call my hands to lift and perform a greater movement than just lazy scrolling.
Well, no unbearable demand, but the process and comfort of reading is influenced by lazyness to a very large extent.