[Imp]

10 for tubes
Rockets are generally 10 to though some are 18
Tubes are marginally more effective due to bigger warheads.

Fairly important as about 5-10 years after they come into service main players MBT generally need a hull hit to take them out. 7-10 top hull becomes the norm.

Best uses in my view really are vs priority targets like ATGMs & SAMs or vs troop transport.
Still useful vs second world or some old MBTs but best to try & coordinate with ground forces so can attack survivors while suppressed.
Russian T0S-1 flame rocket is scary & handy for things like river crossings.
High hard & soft target kill & suppression so survivors are open to attack, any surviving infantry are probably blinded by smoke & fires which can even effect TI if LOS enters enough hexes