Great question — answering as the UphillTech team:
Looks reasonable, other than the (hopefully just a sketch issue) shower trap looking S rather than P on the sketch. Presumably the drawing fails to show whatever constraints keep the shower connection from being more direct ( i.e. from the sketch, seems like the Wye could just roll over to point more at the trap and simplify your connection, but I assume there are obstacles. If there are not obstacles, do that - it does not need to enter the 3" line facing up - 45 degrees up towards the shower would be dandy, 2 degrees up towards the shower would also be acceptable - it IS a wye. They do that. Taking the dry vent wye off the top is correct.)
Full answer by Ecnerwal: https://diy.stackexchange.com/a/206652 (CC BY-SA 4.0).
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