Do not do it unless you want a dead Chevron Tang. Chevron should have been one of your first Tangs in the system. They are wimps comparative to the other Tangs.
Just made this suggestion to someone else. If you really want the Chevron, you can try to add it to the tank with a mirror on the front of the tank. Aggressive fish will leave it alone as long as the mirror is on the tank. That should give it a fighters chance of survival.
The sailfin will likely be your problem here, but also would count out the yellow tang either. Chevron Tangs usually are introduced into system much smaller than other Tangs because of their size. If you do not care about the colors, you can get a bigger one and that will help out for sure.
Also, I'd suggest if you are going to add more Tangs, add more than one. It'll help spread aggression as well.