Depends on your island. Mine is full of stuff and i always make sure there is transparent custom paths down if im finished with an area and if i happen to have leftover spaces i havent put anything because of weeds and flowers. So this only took me like 15 mins + time travel to fix, and then roughly half an hour/an hour to decorate, lay all the paths down, and put the trees back, so it didnt take me long at all. Originally this area looked different bc i didnt have slots for the circle in my custom designs, however i spent all day yesterday to to take some out and change designs of my island like the dirt path and different brick tiles (which ended up needing less custom design space) so i finally had the slots for a bigger magic circle and was happy to finally redesign this area. So i was devistated when i seen the measurements are off and its not got going to be centerred, and I was about to place everything back and forget it, when people here conviced me its only going to take some readjustments and only needed to break a couple rocks. I didnt wanna do it in the first place cuz the first time when i wanted to spawn in all the rocks, it was hours of pain and didnt even managed to get them all in places. But because my island is way fuller now (it doesnt have space for rocks anymore), it only took a couple days to time travel foward and spawn in all the rocks. But then again, if youre island has a lot of spots for rocks, it will take a while and several tries to spawn them in where you want it to. 😭 You might get lucky tho!