Konfident Kook

Hi! I'm cooking a 3kg whole tenderloin (we call it eye fillet in Australia), by searing the outside quickly then baking on a rack at 190 Celsius. I have read that for rare I should allow 15-20 mins per 500g of meat (so 30-40 per kilo) - has anyone out there cooked a whole fillet that weighed 3kg, and if so how long until centre reached about 55-60 degrees C? Looking forward to hearing from like-minded beef eaters!