For the record, I wasn't suggesting applying "800 wounds to one model"
I was merely suggesting allocating wounding hits as you would normally. If a squad of multiwound models takes two wounding hits, they would both go onto the same model, then armour saves are made, correct? Yes, of course. At no point did I ever suggest assigning more wounds to a model than it normally has.
The confusion lies in where the instant death rule actually comes in. Do you account for instant death as soon as the wound is scored (at which time it goes from being one wound to two, three or however many the model has), or do you do it after the armour save? I always treated wounds that cause instant death the same way you treat any other wound, *until* you fail your save, at which point it kills you. So if you treat an instant death would like any other wound until after you make your saves, then assigning them both to the same model makes perfect sense. Your squad has suffered two wounding hits. The rules say apply them both to the same model. The rules go on to say that if he fails his save even once, he dies.
I guess the question is, is the instant-death wound still only one wound (which now carries a special effect) or does it transmute itself into multiple wounds? Since you only get one save against an instant death wound, I assumed it was only one wound. Just a wound with a special effect attached for when you fail a save.
That's how I run the rule. I could be wrong, but I'm sure you can see it's not a terribly unreasonable or abusive reading. I wasn't able to find anywhere where the rules directly talk about assigning instant-death wounds in a multiwound squad. I simply assumed you assign wounds as normal and apply instant death at the first failed save.
As I said, I'm willing to accept that I was wrong. I just don;t want people to think I was attempting to be abusive or apply completely insane logic to the reading of the rules.