The amount left in the crankcase is controlled by the pipe length on the big drain bolt in the cases.Not sure how much should be in there but 200cc does not seem excessive.If there is too much oil in there,it would show up by burning a little more if the flywheel was picking up oil and flinging it up the bores.I would run it a bit more and just check that oil in the tank stays at a constant height with the engine running.People on the triumphrat site frown on removing the big drain bolt as dirt can get in the pump.I have never had a problem over 30 odd years running a T120 and taking out the drain plug.Post this up on the rat site and see if any other suggestions