Multi war base

can you switch war bases during war prep with the multi war base option?

Yes, you can switch war bases during prep right up to the last minute. That is why you will start seeing very interesting looking bases during prep time.

This is a fairly good strategy, actually.
And a somewhat overlooked advantage to the multi-base options.

I do a lot of scouting for my clan. I look at every base, including our own, multiple times during prep day.

If you waited until the last minute to change them, all my work is useless and I have to start over again.

no but in prep you can switch all you want but once war starts you're stuck with the one you chose
so choose carefully and may the stars be forever in your favor

Switching it won't make a lot of different. If clan are good at war, they will wait and make their troop at the beginning of war.

You definitely can!