Fish First is right. No offense but surviving anf thriving are totally different things. just because you have great skimmers and equipment like that doesnt grant the tang extra swimming room. the only way to give the tang extra swimming room is to give it a bigger tank. If the fish gets too large you would buy another tank? So what happens? the fish dies before it reaches adult status? As you mention getting a 200 gallon as if its no real problem then why not start out with one? I would not dream of housing a tang when i had my 40 gallon, i got the 100 gallon for the very reason to house a tang, i very quickly realised that this was not enough room to be honest so the 220 gallon is under construction,
I really am not trying to offend anyone buts its extremly important to draw a line on what size tank a tang can thrive in. Saying that a 75 gallon is almost as large as 100 gallon only wokrs for a while.. then someone will say.. well my 60 gallon is almost the same size as the 75 gallon that "he" has his tang in.. and later on.. Well my 40 gallon is not far off the 60gallon that "she" has her tang in.. eventually we see tangs in 10 gallon tanks! (and yes i have seen this happen).
No, sorry, they minimum for a tang (with the possible exception of a Kole) is 100 gallons anf this is borderline really.