>>19680
A /tg/ CYOA is not exactly either of those things, and is more like the question of whether you'd fight a hundred duck-sized horses or one horse-sized duck but as an image or PDF. The latter that you gave is a quest.
Back to the question at hand, I'd be interested in the pre-written one a bit more. I guess my advice would be to keep them short in the sense that the individual route lengths are short, but the number of choices are relatively plentiful. The appeal of pre-written is seeing where the choices lead and it's replayability so read length can bit a bit shorter than the typical story. If you're going for a quest whether that be a singular character or multiple joining in, having a general outline of the scenes or set pieces rather than the stories is recommended. Also kept short so that you don't burn out in the middle of it and leave it hanging.