I am delighted this is catching your interest.
July Mazzeppa sounds great. I don't play it, but I am sure there are many that do.
The spirit behind the random list I put as January to June is pieces that many people may know (or should, like Mozart-Thalberg), avoiding too much repetition of the same type of repertoire, and mixing harder and more accessible pieces. My original idea was one to four pieces a month, one from CPE Bach and earlier, one from CPE Bach to Beethoven, one from after Beethoven to before Debussy, and one from Debussy to today. For composers hard to categorize, put them where you think you should (I put my Albeniz before Debussy and my Weber after Beethoven, but no limitations in that sense). You choose whether in any given month you post 0-4.
But then, there was the concept that it is hard to compare the playing in different works. Hence the single piece list.
I like the idea either way, and perhaps what we should do is have them both.
I do not have a particularly large repertoire, and more importantly I do not keep it in shape, although these days I am playing Debussy and I do plan to be in fine shape by January 31 to give anyone interested 9 minutes of L'Isle Joyeuse how you have never heard it before.

(I play it really much slower than anything you hear in recordings. It makes no sense to me anymore at a 5 minute clip).
What about August: Amy Beach Op. 83 and September: Saint-Saens Op. 70 (that's the one you mean, right?)?
I am trying to avoid back to back pieces from the same period.
I do play everything I listed Jan to June (except the Mozart-Thalberg, which I should), but I would be very surprised with myself if I posted for all of them, as I am unable to keep a lot of repertoire in fingers. I do not play Mazzeppa, Beach or Saint-Saens, but this would be great motivation to read them.
Do it. It will be fun.