We have been using the new combat simulator to determine effective armies. The way combat works currently isn't the same as the new combat. Basically damage is spread across a lot of ships at once in the current system. While 350 Battleships could be good if someone doesn't have enough orbitals, in the case of stealthed orbitals it could prove to be deadly.
Under the new combat system stealth orbitals will only have an initial 1 free attack round bonus. If the orbitals are stealthed, and their orbital stealth skill is higher than yours they will get a free round, where as if you have a higher or equal stealth orbital ability they will not get a free round of attack.