With the exception of large tanks(200+)IMO
most successful multiple tang stockings use tangs of different shape.
2 sailfins in a 85 is bold to be polite IMO
(and risky for whole tank ).
I infected my 120 with marine ich by adding a tang that just wasn't going to be appreciated by the other tang.
Lost almost every single fish!
The two tangs were worth $300 alone...
It was from the stress and aggression not bad /unhealthy fish.
I also just recently lost an 8 year old clown and have another single in a different tank.
I am hesitant to add the two together?
I have seen mindless clown stocking go down with out issue and had clowns that killed any other that entered no matter how well planned and executed.
Are the clowns the same species?