350 beds for the girls and 400 (max) display cases for their jewelry. I'm really short on jewelry storage though, I definitely can't equip every girl with a full set, which I find pretty weird game design, especially considering the storage costs flower gems.

The reason I have so much place for girls is pretty simple: I stock up on upto 10 of each dragon, so that's 3* 3 * 10 = 90 slots reserved for dragons, as well as upto 10 of each ampy, which means another 30 slots reserved for ampies (As soon as any girl evolves, she gets one of each ampy, so the number fluctuates quite a bit). I also always keep the number of ampies for each type equal to each other. If I have more ampies of one type than of another, I put them on the girl who makes most use of that type of ampy.
Then, there's the thing about regular farming and the occasional seeds gacha spree: I like to have space to do at least 3 10+1 pulls , so that's 33 inventory space I like to keep clear. Preferably more.
Oh, and I kept at least one copy every girl I ever obtained, so I still have all my 2* girls as well.