Critical hits in OGRE

As originally written, OGRE is a game of attrition: You have to wear down the oncoming cybertank piece-by-piece before it reaches its objective.  Unlike traditional tank games, there's no stopping the looming behemoth with a single shot, at least in the official rules.

And this makes sense: If you can take out the OGRE with a single thought, there's no deciding whether you should spend your attacks on the treads to slow the juggernaut down or use all your shots to target the guns and declaw the beast; it's just an exercise in rolling dice till it'd dead.

Still, in big games with multiple OGREs, a critical hit rule can add some excitement to the game: while it's an all-or-nothing shot at the cybertank, it's not an all-or-nothing roll to end the game.

I've found two different ways to resolve critical hits on OGREs; both are on the SJG website:

• The Golden BB: Roll three dice to beat a target number based on combined attack strength (the higher the attack strength, the lower the roll needed), if you fail, the OGRE's not affected.  The attack roll gets a bonus against smaller OGREs, a penalty against larger ones.
• Poor Bloody Infantry: Roll attacks against the OGRE as a whole--but the OGRE has a large defensive strength (double digits for all except the Mark I).  If you do get a hit, you still might have to roll a d6 to see if you knocked out weapons, or movement, or killed it, and there's a chance it's undamaged.

Myself, I'd like to see a combination of the two rules: Attacking units can combine their fire, and the higher their combined attack strength, the likelier they are to score a critical hit.  But even if they do, they still must roll to see if they damaged it permanently or temporarily, or at all. 

That should provide some tough decisions for players: wear down the OGRE a little at a time as usual, or risk everything for a chance to take it out all at once.  Which would you choose?