@Sgisela and @Animisha thanks for all of the comments!
Sgisela My worry about Reminiscence (if the YouTube video was cued to the right place) is that to me, it sounds much, much more difficult than the Ffrench pieces.
I'm pretty sure it's cued up right, it starts at 1:40 (ish) for me so hopefully it's the same for you. (the video information is actually mislabeled, it's written in Japanese so I didn't explain that, but it lists Reminiscence as first when actually it's second in the video as a whole)
Anyway, interestingly enough, I agree that Reminiscence might sound more difficult, but actually, it's a fair bit easier than September Song. To me anyway. It's a little difficult to explain why, but one reason I think that is because Sept Song is more harmonically complex, and has these inner voices that are shared across both hands. So I find Sept. Song much more difficult to read. Also there are several themes which get repeated with very slight variations, and that coupled with the inner voices shared across hands, makes it easy to get tripped up. Reminiscence doesn't have any inner voices, for one thing, and it is very easy to read. I think maybe the parts where there is a run or passage with a lot of momentum make it sound harder, or maybe a little flashy.
On the other hand, Sept Song sounds a little slower and calmer but there's a lot more going on. And it requires more control and voicing, something which is pretty challenging because it's such a quiet piece.
BTW on the topic of reading... Notice I mentioned a few times about how easy or difficult something is to read...
In case anyone is curious, I won't be memorizing these pieces. Despite the fact that I already have them passively memorized. I have found that I do better when I have the score out and I actively read it while performing. That helps me in a variety of ways. For one, I kind of get shaky hands, and not having to worry about memory flubs takes one worry off my plate. Another benefit is that it gives me a place to focus my attention, which helps me concentrate on the music rather than getting distracted and thinking about how nervous I am or something.
I also like to return to pieces, and if I memorize them, I find it harder to revisit the piece after putting it aside for a long time. But since I'm a pretty confident reader, revisiting a piece means I just read-play through it, and I have been doing that for years now. So I always read when performing. (I do have an iPad and bluetooth page tuner as well).