How do you get 6/4? Lined Coat gives you 4/2, and full FFBA gives 4/1 (halved to 2/0), giving 6/2. And Full Suit FFBA has a hood, granting head protection.
Whoops, sorry about that. I went back an looked at Gabriel's sheet and it is a 6/3. Rounding down armor is stupid, and we don't do it. So we still devide by 2 for the layering, but the armor will provide a minimum of 1 point. So the rating comes out to be 6/3. As for the head, that is straight FFBA if we are wearing the hood/goggles at the time.
As for figuring out hit location, we use the original BattleTech hit location table. It gives a 1 in 36 chance of hitting the head naturally, but most damage goes to the Left/Center/Right torsos, so armor tends to be used as normal. The fun comes in when you hit an arm, leg, or head. The way we figure it, no matter what kind of armor you have on your head, a bullet hitting it is going to hurt, so no matter if you shrug it off or not physically, you still get Stun damage equal to the unmodified Damage Level. So being hit in the head by a predator will give you a Medium Stun no matter what, you still have to shrug off the nomral physical damage in the normal way.
Gabriel