I am turning my old master bedroom into a new master bath and need some advice on wet venting connections. I have a 1 1/2" vent through the roof feeding the lav sink, 2" inch below the sanitary T into the crawlspace. It will connect to the 3" branch, about 2-3' downstream of the WC. The tub and shower drains will connect to the 3" shortly downstream of the wet vent connection, and the 3" will enter the main stack. My question is, does the 2" wet vent to 3" require the Y to be horizontal or rotated above centerline of the 3"? Also, do the tub and shower drains tie in horizontally, or should it come in from above? The wet vent will be serving a WC, tub and shower. Trap arms to the 3" for the tub and shower are 3' or less. Thanks for your help! If you know where I might view a diagram as well, let me know.