I am plumbing a new bathroom in an existing space. The best/easiest place for me to vent the toilet is in it's vertical drop between the joist. From there the drop continues below the joist(less than 24" of drop) before going horizontal to the stack.
I have a shower and a sink that will be connected via a 2" line that will be used as the wet vent.
I know that a toilet is normally vented in the horizontal with the vent tying in above the center line.