At Swim-two-birds

I just finished reading At Swim-two-birds, and what a phantasmagorical book it was. It's hard to avoid a comparison with Ulysses, particularly the "Oxen of the Sun" and "Cyclops" sections, but O'Brian is taking his own path. Joyce is using the language of epic to describe a quotidian day, and somewhat to obscure what's really going on. It's easy to read those episodes and miss important entrances and exits, or to miss important dialogue. But in At Swim-two-birds, it's never unclear who's talking or what's going on.

Instead, O'Brian is playing around with the whole concept of authorship. Are the self-consciously labelled autobiographical sections really autobiographical? And does it matter? Do they tie into the fictional part? And, if so, which fictional part?