Another thought for the same issue - what is the proper use of a sanitary tee or long sweep tee? I am thinking of running the vertical vent into the "radius" part of the sanitary tee, with the tub drain entering upstream of the radius. This is essentially what I have now, but instead of a sanitary tee, there is a brass wye. Problem I have is the location of the wye is creating issues in getting the tub drain connected without relocating the vent or wet drain pipe (after the wye) in a major way.
Here is a thread talking about something similar. I want to put the sanitary tee horizontally, with the sweep arm vertical, or nearly so. The vent would enter the sweep arm from above, and would be directionally correct. The drain would flow through the "straight" (my words) part of the tee.