The necessary skills
One of the most important skills for tankers is "repair" and "masking." If "camouflage" for the heavy tanks are out of date, "repair" will always be a way. So the first perk for the crew should be "repair". The ability to quickly repair the tracks and hide the tank can cost lives in battle
Next is to develop specialized skills. For commander – sixth sense, to get timely information about the detection. For gunner – "snap shot", and for the driver – "smooth running". This will allow less overshoot in the movement and combat maneuvering. For charging – "desperate" to have the ability to quickly reload, left with 10% of the strength of the tank.
If the tank is often used aggressive tactics, as the third perk, you can put "combat brotherhood". In combination with improved ventilation behaviour of the tank in combat will gradually improve. If the preference for the base defense, instead of "brotherhood" bleed "masking". In combination with the established telescope can operate in the mode of PT-ACS and act in ambushes.
Usually the crew of the seventh level rarely pumped for more than three perk. But for fans of ISA can offer the next set.
Commander should improve the review not to get into a situation where the tank will shoot the invisible enemy. This is "eagle eye" and "intercept." To increase the survivability of the machine, learn the skill of "Jack of all trades".
The gunner will be useful skills "sniper" and "gunsmith". The first skill gives bonus damage to the enemy, the second to reduce unpleasant consequences derived from building guns.
For driver – skill "king of madness". It is known that the permeability of the ISA on weak soils is small. "Virtuoso" will not allow light and medium tanks to heavy spinning machine. "Master RAM" in combination with the equipment "heavy spall liners" will provide an opportunity when a battering RAM to cause 2-3 times more damage than losing the tank.
For the gunner skill "intuition" and "contactless ammo rack".
These perks are relevant not only for ISA but also for all the subsequent tanks in this branch of development for the is-3, is-8 and is-7. But if you decide to pump the crew of the ISA to the state of "Rambo", one of the perks of the commander replace "mentor". It manifests itself fully after a few thousand battles.