we usually get one about 1-1.5kg and cook it on very low for about 2 -3 hours. DH and I both like well cooked meat (no pink in site!) but still moist so we really do work on guess work! we've put todays on about 10 minutes ago, and will check in about an hour, flip, then about an hour after that - at that point, we'll check for red/pink liquid at the thickest piece of meat.

if you're concerned about getting it cooked right in a shorter time, you can split the roast between the bones of the ribs - and seperate a bit as there is then more surface area to cook (hope that makes sense!) - todays is bigger than normal (more meaty than normally get at Tasman - the butcher loves us lol) so we'll cook it longer than normal. i just asked DH how much it weighed and got "i dunno - i just told webby i wanted a rib eye roast!" - good on ya hunny! from what i could see it would be between 1.5 and 2kg...