elpenguino: 
Let me see if I can find a reference.

Here's the table from the 2007(8?) standard

This is the kind of thing your sparkie will use.

Note that the standard says even if the wall is un-insulated the the sparkie should plan on it becoming insulated if that is 'reasonably foreseeable'.

Personally, I'm interested in maximising insulation performance due to the long term benefit it brings. I spend time making sure batts are perfectly filling voids without gaps or over filling either.

I'm also that guy who buys cans of expanding foam and goes around top and bottom plates, window and door frames, the edges of the flooring and between double studs getting into the cracks that are inevitably to be found.

No draughts for me.