It's higher than 40.

I don't think anyone knows for sure, but quite a bit of research test they have done used over 40g at a time.

Plus say you eat a steak, that sits in your stomach for a long time.

I like 20-30 grams when "off" cycle
and 40-50 grams when "on" cycle per meal

i think it differs from person to person though

The bigger you are the higher your protein digestion, simply because of a larger surface area in your intestines. Also if you have been consuming large amounts of protein for a long time, your body's ability to process protein increases. A good bu t gross test to see if your are consuming to much protein is to have a look next time you deficate. If you pooh floats then all of the nutrients have been absorbed, where as if it sinks your stool is still pact full of undigested proteins, carbs, and fats. Bad gas is also a sighn of protein overload.