What to pay each player isn't an issue because each should get an average salary of $10 million per season based on potential and what he brings. Whom to take care of first is the issue.
I'd say the left tackle.
Smith's contract isn't up until after the 2014 season, but the Cowboys have an option for 2015 that can be picked up in May. Smith was ranked the fifth best tackle by Pro Football Focus in 2013, when he allowed one sack, three quarterback hits and 27 quarterback hurries.
Taking care of the left tackle long-term is important with quarterback Tony Romo coming off back surgery. Romo's issues with the protection wasn't the tackles, it was the interior, which was solved in 2013 by the excellent play of center Travis Frederick.
But Smith's play, which earned him a Pro Bowl berth, was the best on the offensive line. The Cowboys need Smith, who turns 24 in December, to command the position for about 10 years. He's a stable player on and off the field, which is another plus for the Cowboys.
Locking Smith up at this stage makes the Cowboys look smart.
This isn't anything against Bryant, who is an important player as well. But once you have a quality left tackle, you better sign him for a long time.