[Oxymoron]

Hi there, I have a 90 gal with 30 gal sump, approx 150 lbs of live rock (about 10 in the sump and 140 in display)and aprox 120 lbs live sand. Tank dimensions are 48"w 18"d 24"t.

I have plans to upgrade to a much larger system in approx 2 years.

Through my research it seems that some people have the opinion that no tang should be kept in a 4 ft tank.
On the other hand several reputable business's (mind you they are in the fish selling business) suggest a lower amount of gallons to care for these fish.

I am hoping to be able to keep 2 tangs in this tank and start them out at around 2.5" and eventually transfer them to the new tank when the basement is completed.

I was wondering about this forum's opinon on the matter.
Is it possible to keep 2 small tangs in this tank?
Which tangs would you recommend due to the size constraints?
Does anyone else have a similar build with 1 or more tangs in it?

Thanks all for the opinons they are always appreciated.