It looks like the NBA accountants did their magic with respect to calculating the Basketball Related Income for the 2013-14 Season and have thus determined the 2014-15 Salary Cap, Luxury Tax (with the implied Apron set $4 million above this), and Maximum Salary for respective groups of players.
Per @NBA: Salary cap for 2014-15 season jumps to $63.065 million. Tax level is $76.829 million. Minimum team salary is $56.759 million— Chris Mannix (@ChrisMannixSI) July 9, 2014
Further, the Maximum Salary for a range of players has now been set:
|Years in NBA||Defined maximum salary||2014-15|
|0 - 6||25% of cap||$14,746,000|
|7 - 9||30% of cap||$17,695,200|
|10+||35% of cap||$20,644,400|
(Source: Larry Coon)
With these values set, Danny Ferry can now determine his game plan for the rest of the offseason. While the NBA projection of $63.2 million from a few months ago was a bit optimistic, this still represents an almost 7.5% increase from the previous season's Salary Cap of $58.679 million.
Before the Thabo signing (which has yet to be announced), the Hawks potentially had between $45,045,282 - $68,207,564 in Team Salary. This means, that the Hawks could have at most $18,019,718 in Cap Space. With this amount of Cap Space, the Hawks would have been able to sign any player with less than 10 years of NBA experience to a maximum contract.
But as I have mentioned before, the maximum cap space scenario not realistic. The maximum amount of Cap Space for the Hawks implies they would have renounced all Free Agents (Ayon, Brand, Mack, Scott), draft-and-stashed Payne, and waived Pero and Salmons. In a more realistic scenario, the Hawks would waive John Salmons, keep Pero and Muscala, and have the capholds of Payne, Mack, and Scott still on the books. This scenario leaves the Hawks with $48,075,564 in Team Salary for Cap Space of $14,989,436.
While we still wait for the Thabo signing to be officially announced, recall that a rumored 3-year $12 million deal could start anywhere between $3,809,524 -- $4,188,482. So the Thabo deal will realistically bring the Hawks Cap Space down to the neighborhood of
$10,800,954 -- $10,421,996 $11,179,914 -- 10,800,954 (7/13/14 corrected for arithmetic errors).