Ha! Do you know how many times I told DH with both of mine that we needed a 23h day?!
So true....
It doesn't sound like she is super low sleep needs as she is getting a fair amount of sleep in total - perhaps not a high sleep needs baby though
She could well be one who prefers a shorter night and more of her sleep in naps - my DS is very much that way whereas DD was completely the opposite - had about 1.5-2h daytime sleep at 8 months but a good 12h night or more sometimes.
I think there are two ways of looking at it really - one is just to ride it out, accepting the cycle of good and bad days, and look forward to getting to one nap in the next 6 months or so. I found with both of mine there was much more stability once we got there, and it was easier to set a nap time at that age. The other option is to try a set nap(s) which at least may stop your day getting too much earlier and gives you some predictability - though I will say it does not mean every day will be the same! Mainly the stability comes from knowing when the nap will happen, but the length can vary from day to day.
Some people have had success with setting the first nap, then being a little more flexible about the second depending on how the first one went. In order to set the nap you basically work from ideal WU time (7am?) and set your nap based on a typical A time. So maybe nap at 10/10.15am. For it to work you ideally want to leave LO in bed until ideal WU time so that they can handle the first A time ok even if they wake a touch early. If LO is clearly tired or wakes very early you can pull the nap earlier by 15 mins or so - but any more really isn't 'set'.
Be aware that often older babies and angel/textbook types deal with set naps better than younger babies or those with a touchy/spirited streak. We would generally suggest to use A times at this age - but I do think set naps can be very helpful for some and certainly worth a try.
What do you think?