Junot Diaz, author of The Brief Wondrous LIfe of Oscar Wao (highly recommended), has an interesting bit about his writing process in an interview (Callaloo, 23, 892-907). He says that in his editing process he will look at a sentence without looking at the composition of the sentence. If the sentence does not look right on the page then he will change it so it does look right. I wonder of this is common and I suspect it is more common than many writers realize. Note, this is not same as pacing, keeping paragraphs from being too long and too short.
Bolano, however, does not do this. In the beginning of the book there was more dialogue that looked normal, with line breaks. But as the book progresses there are less and less with dialogue looking more framed than acted out. The paragraphs are also decreasing in frequency as the passages are becoming longer in composition but shorter in content and plot devlopment. The book now seems to be a collection of anecdotes about the characters as they move towards the inevitable, which I now believe is going to be a gruesome bloodbath. I will admit an excitement to see what he does and how he does.