I used a T on my only cowled plane and the fuel come out of the extra line at the same time as it comes out of the muffler (knowing this I really don't need the T)
The amount of fuel in your muffler, if you stop fueling right away when it starts coming out, is minimal (less than a teaspoon) and will blow out when you start the engine.
IMO all the extras are a waste of time and just more things to fail in the future.