OzTrail mat under the tent, CCmat under the annex. Both work a treat.
Used to have a silver tarp under the tent, but the first time it rained, the rain ran down the canvas and under the floor and pooled there (the tarp was bigger than the tent floor). The OzTrail is also bigger, but the water just soaks through it and does not pool.
Like the idea of folding the extra over near the wheel. Will try that next time.