TOTALLY BAD IDEA? - Mixing Regal Tang and Powder Blue Tang

[Seek828]

Hi all,

Just came back from my LFS today and found that they have gotten some Powder Blue Tangs. They rarely get them.
They are slightly less than 3 inches long.

I was just getting ready to get my next fish for my 90G FOWLR and initially was thinking the Regal Tang (Paracanthurus hepatus).

They also have one at around 3 inches long.

I really like both. But I know that with the similar color and body shape, there is a high possiblitiy that they will fight.

Anyone think there is any chance in the world that they will tolerate each other in a 90G? Anyone tried keeping them at the same time before?
What if I add them together at the same time?

Thanks for reading!