1. it is definately coming from the base of the toilet, i have watched it slowly seep out. and the back and side of the bowl and tank are dry.
2. when using the upstairs shower, water will leak from the base of the toilet AND the downstairs tub has water backed up into it.
3. the leak only appears when someone is taking a long shower. the leak will appear approximately 7 minutes into a shower, then water will start to steadily seep out from the base of the toilet. i come back 1 hour later and flush the toilet while running the water in the downstairs shower, but the leak doesn't appear. i come back another hour later and flush the toilet 4 consecutive times, still no leak. so the only time there is a leak is during long showers.
4. pouring draino into the downstairs shower does nothing!