I just reread the MgT2 vehicle combat rules. You're looking at the Central Supply Catalog, which I don't have ready access to right now.
I'd say that if you want to assault a vehicle with TAC missiles, here's how you do it.
1. Don't fight fair. Get into a good position to gain any kind of modifiers the referee will give you for tactics or anything else.
2. Aim for parts of the vehicle that have no armor, or weaker armor. By the rules (p134), the roof and floor use half values for armor.
3. Criticals mean everything. Any attack with Effect of 6+ engages a Critical Hits Location roll, and extra damage from the critical hit ignores Armor. Any kind of DM increases Effect (so see #1). Aim for +1 DM. Closer range also lowers difficulty of rolls, and thus increases Effect.
[I wrote this and then realized you probably don't need the 101, so I apologize in advance.]
A TL12 laser rifle does 5D+3 damage (average 20). That won't penetrate the 50-70 AP of an Armored Fighting Vehicle (AFV), even on a max roll (33 + Effect). Still, it will cut through a regular car (2 Armor) like butter.
Heavy weapons are required to take on armored vehicles. Still, rockets appear to deal 4D or 5D damage, which doesn't threaten an armored tank. The PGMP and FGMP deal 1DD and 2DD damage, respectively.
Vehicle-mounted heavy weapons include heavy SMG (4D, Auto 3), light autocannon (6D, Auto 3), cannon (1DD), laser cannon (1DD, AP 10), and fusion gun (3DD, AP 20). Note that the AP means "armor penetration" and that is the amount of vehicle armor that is ignored before determining what the armor soaks.
When damage is DD and not D, it's "destructive." You don't add Effect to that damage but you multiply the damage by 10.
So you shoot at an AFV (Hull 60; Armor 50, 60, or 70, depending on facing) with a laser cannon (1DD, AP 10). You hit with Effect 2. You roll 1D damage and multiply by 10. Say you get 30 damage and hit the rear (Armor 50). With AP 10, you are facing effective Armor 40, so 30 damage doesn't penetrate. Roll a 5 or 6, and you're dealing 50 or 60 damage against Armor 40, and 10-20 is getting through. 3-6 hits like that disables the vehicle. Or get a critical hit and start rolling on the chart. AFVs are really tough.
The G/Carrier has Armor 80-120. I have no idea how you damage this thing. Try to get underneath it in the back, where the Armor is 40, with a nuke?
Really, why are you shooting at TANKS with hand-held weapons?
A PGMP against it would deal 20-120 damage a shot, though. Pocket nukes deal 6DD (60-360).
Does Central Supply really list RPGs and TACs as non-destructive damage?
And what's this D8 business? Do you mean 8D (8-48 damage)?