First off, thanks for any and all help in advance. Quick back story, my wife and I bought my godparents 1910 homestead/ farmhouse and are in the process of gutting and remodeling the second floor as the first floor was done back in the mid 90's. The first floor includes a new addition and two new bathrooms. They both have PVC plumbing that was coupled to a 4" cast iron soil stack that transitioned into the 4" vent stack through the attic and roof. I've gutted the second floor bathroom and am relocating all plumbing fixtures. My issue that I need help with is the toilet run. Where I'm placing the toilet is about that 2' - 2 1/2' from the soil stack and about 4 1/2 - 5' from the vent stack. With the toilet so close to the soil stack, what kind of slope should I be trying for to get it to drain properly? I've tried the 1/4 off bubble, but that seems a bit to steep, and 1/8 off bubble doesn't look right either. I've two runs set up to experiment with. The first is a 3" that transitions up to the 4" at the soil stack, and the second is a full 4" run. My second question would be the venting of the toilet itself. Would it be possible to use the same drain line as a wet vent since the actual vent line is so close? Oh and before anyone comments, I didn't cut the joists. I'm guessing they did that when they brought the plumbing into the house way back in the day.