Venting for new half bathroom

[aliebling]

I'm installing a half bathroom (converting pantry) and am trying to figure out how best to handle the pipe and venting layouts. Ideally, I'd have the main stack also be the venting with only wet vents to the toilet/sink. I think wet vents work if the sink and toilet both go directly to the stack and the sink uses a 3" pipe (since both connections are less than 6').

If that is correct and we use just wet vents, I assume there is a limit on the vertical drop from the fixtures to the vent ("The vent pipe opening from the horizontal wet vent, except for water closets and similar fixtures, shall not be below the weir of the trap."). If that's the case, how do I determine the max drop and can it involve bends or must it be a straight pipe? Also, "except for water closets" implies the toilet can connect to the stack at any vertical offset and I only have to worry about the sink, correct? If that is correct, can the toilet take a vertical bend in the middle before connecting to the stack?

If I'm totally off base, given the locations of the sink, toilet, and stack; what is the best combination of pipes and vents to use? That said, I'd really like to prevent having to add any other vents other than the stack.

Please excuse me if anything is unclear - this is by far the biggest plumbing project I've taken on and I'd like to get it right.

Thanks for any input!

P.S. I had accidentally posted this in the IPC forum previously, but I believe California is based on UPC.

 

[Reach4]

If stack does not contain drainage from an upper floor, 2 inch vent and drain on the sink (lavatory) would be good, but I am not sure 1.5 would not be sufficient.
Toilet connects lower than sink connects.
A wye for the toilet is best, but santee is OK.

If stack may contain drainage from an upper floor, I think the (waste+wet vent) line from lavatory joins toilet waste before the stack with a wye. Lavatory vent and drainage would be 2 inch.

I am not a plumber.