Jump starting - which manual is correct?

[HIFI]

Need to jumpstart the Boxster (don't ask!), but the manual for the Porsche and my donor vehicle do not agree with each other??

I am inclined to trust the Porsche manual, but just want to make sure.

The Porsche manual says the Good battery should not be hooked up at all to the negative lead and the Bad battery's negative lead should be hooked up to the ground.

The Chevy manual is basically the opposite (Bad battery no negative hookup, Good battery negative to ground).

Which is correct?!?

Also, I know I am not supposed to start the Donor car while connected, but how long do I let the two stay connected, before I try to start the Boxster?

One final thing, is it going to hurt the battery further if I wait until tomorrow or should I jump it ASAP and drive it for a while to re-charge?

Thanks!