Just a general question on how the rules work in regards to using personal scale weapons against vehicles, because I was always under the impression that missile tubes and heavy repeating blasters were portable anti-air defenses that could be used to knock out fighters, and even scare away larger starships. (In Rebels the Ghost gets damaged by E-web cannons and has to retreat, in Rogue One they shoot the leg off an AT-CT with a side gun on a transport, though a shoulder fired missile fails to harm the walker, in Force Awakens Poe's X-wing gets blown up by blaster fire) By SWRP rules it seems that a missile can't actually really damage a TIE fighter though, it just has too much armor. So, just a question on how the rules work here:
A missile tube has damage 20, breach 1, and is a personal scale weapon. A TIE-fighter has vehicle armor 3, which means even after breaching 1 of those, the missile barely just breaks the TIE fighter's armor.
So here is the question: Do I need to roll 10 successes on the missile shot to actually do damage to a TIE fighter, or will a lower number of personal scale damage count?
If personal scale damage does count, is the TIE fighter treated as having 60 hitpoints when taking personal scale damage?
Can I activate a crit off the missile if I only inflict a few points of personal scale damage with it?
And most importantly: Is there some kind of rule about using missile tubes or other personal scale weapons against vehicles that I'm overlooking entirely?