There's no specific amount. At least 15 would be nice I'm not sure where you can put them, so anywhere that's free(town is still a mess from not being able to play much lately)
A bunch of random fossils work I'm working on my Inktober drawing, so I'll be afk a decent amount of time(and trust you won't do anything?) I have Mabel in my campground if you'd like to visit her. The daily RV is Saharah's I believe?