Thank you, Mike! Section 7 is PL OK!
A couple of other thoughts as I know that you're wanting to take this further. You're getting into the realm of where there isn't a "best" microphone but the question moves to which one's colour is best suited to your voice. The NT1A is very bright and I think that suits your expressive style of reading well. When I tried one, it really made my "s" and "th" phonemes hiss badly, but you seem to have tamed that either with good mike technique or a substantial pop shield.
One disadvantage of reading in a lively, expressive manner is that it can create larger dynamic ranges between the overall volume and the loudest bit. Librivox is quite forgiving on this - providing that you're not clipping and ReplayGain is within 2 of 89 you're OK. Others are a bit fussier and would require you to tame the peaks a little - very little in this case, maybe a couple of dB. The traditional way of doing this is via compression and there are several good compressors around, many of them free. GComp seems a popular choice. I've not found one that works well for me though as they all make me sound a little processed. I've taken to using a plugin called LoudMax (also free) which - to my ears at least - is less distorting. Perhaps it's more gradual on the volume changes - I've not investigated.
The other thing I noticed is that the noise behaves oddly in your audio. I can hear small amounts behind your voice but then it cuts off completely when you're not talking as if you used a noise gate or deamplified when you breathed, We can often be too afraid of noise - the general feeling is that a low level adds a bit of warmth. Both the NT1A and the FocusRite are low on noise anyway so you might not need any noise treatment at all. After recording, normalise the audio and if the noise is quieter than around -65dB then you might want to leave it be. I'm afraid I've not used Reaper so don't know how the noise reduction tools work on it to suggest more than that. Similarly, if your breathing isn't intrusive you don't need to silence every breath. I'm asthmatic so many of mine sound a bit like a death rattle so I copy/paste some background room noise over the worst to keep the audio from going completely silent.
I hope that's helpful - as I said, this is the icing on the cake. As things stand you've already sailed through the PL process without needing further changes.