You can load the portal file prior to testing your map ingame to check your visleaf formations directly from Hammer. The portal file will display the visleafs and you can then determine whether there are too many, whether some are too big, small or efficiently shaped. Allowing you to determine whether or not some brushes need func_detailing or whether some additional hint brushes may be required to cut existing leafs in order to resolve any potential issues that the aforementioned situations could cause. All before you even run HL2.exe and several debugging console commands.