You can actually double dip the whole day of rewards if you know you are going to do it.
Save some Gal war, have an arena and ship fight still available, only do 1 of each challenge etc.
Claim daily reward box. Change your payout. Do all activities again, and claim a second reward.
If you are pushing your payout backwards you can even get fleet crystals twice that day, depending on shard mates.
I did this a few times when I moved my payout for DST. I've settled on a spot the suits either way now, so haven't moved it this year.