If you run it up to operating temp before the oil change, it won't do that. Also you will cause sediments to suspend and be allowed to drain with the oil. In other words, do the job correctly and it's easier.
I don't understand. I though the most easy method was to drill a 10mm hole in the bottom of the crank case. Then just TIG weld the hole back up each time. This way you don't have to tap threads in the case and install a bolt.
This is why they made the case out of soft Aluminum.