After measuring the interior I made an ozan. This is a partial ceiling that sends the rain behind the liner. I really had to wing it here as I had very little info and no instructions, but it works.
This is the bottom of the ozan where it meets the liner. It had just stopped raining and you can see the drips down the back of the liner. Note the pockets I put in the liner.
This is a double bed and a twin cot. You can get some idea of how spacious the 18' tepee really is.